I cannot reproduce this using Chrome 68 on Windows 7. I will update at some point, but it might hint at the regression range.

I could not reproduce this with Chrome 69 on Ubuntu (upgraded from 69.0.3497.92 to 69.0.3497.100 and could not reproduce in either).

matma.rex@ Thanks for the issue...

Unable to reproduce the issue on reported chrome version 69.0.3497.100 using Windows 10 .Attaching screen-cast for reference.
Steps: 
---------
1. Launched reported chrome 
2. Navigated the URL " http://jsfiddle.net/146bnjgu/16/ "
As we are observed that Each of the red squares has a 1px black border

@Reporter: Could you please check the attached screen-cast and please let us know if anything missed from our end and retry this issue with fresh profile. Let us know whether issue still persists.

Thanks.!

Deleted: 890421.mp4 3.9 MB

	890421.mp4 3.9 MB View Download

I reproduced using BrowserStack, using Chrome 69 on Windows 10. My guess is that this is GPU related.
@matma.rex - please, share the about:gpu output.

about:gpu:

Graphics Feature Status
Canvas: Hardware accelerated
Flash: Hardware accelerated
Flash Stage3D: Hardware accelerated
Flash Stage3D Baseline profile: Hardware accelerated
Compositing: Hardware accelerated
Multiple Raster Threads: Enabled
Native GpuMemoryBuffers: Software only. Hardware acceleration disabled
Out-of-process Rasterization: Disabled
Hardware Protected Video Decode: Unavailable
Rasterization: Hardware accelerated
Skia Deferred Display List: Disabled
Skia Renderer: Disabled
Surface Synchronization: Enabled
Video Decode: Hardware accelerated
Viz Service Display Compositor: Disabled
WebGL: Hardware accelerated
WebGL2: Hardware accelerated
Driver Bug Workarounds
clear_uniforms_before_first_program_use
decode_encode_srgb_for_generatemipmap
disable_delayed_copy_nv12
disable_discard_framebuffer
disable_framebuffer_cmaa
exit_on_context_lost
force_cube_complete
scalarize_vec_and_mat_constructor_args
texsubimage_faster_than_teximage
Problems Detected
Protected video decoding with swap chain is for Windows and Intel only
Disabled Features: protected_video_decode
Some drivers are unable to reset the D3D device in the GPU process sandbox
Applied Workarounds: exit_on_context_lost
TexSubImage is faster for full uploads on ANGLE
Applied Workarounds: texsubimage_faster_than_teximage
Clear uniforms before first program use on all platforms: 124764, 349137
Applied Workarounds: clear_uniforms_before_first_program_use
Always rewrite vec/mat constructors to be consistent: 398694
Applied Workarounds: scalarize_vec_and_mat_constructor_args
ANGLE crash on glReadPixels from incomplete cube map texture: 518889
Applied Workarounds: force_cube_complete
Framebuffer discarding can hurt performance on non-tilers: 570897
Applied Workarounds: disable_discard_framebuffer
Use GL_INTEL_framebuffer_CMAA on ChromeOS: 535198
Applied Workarounds: disable_framebuffer_cmaa
Disable KHR_blend_equation_advanced until cc shaders are updated: 661715
Applied Workarounds: disable(GL_KHR_blend_equation_advanced), disable(GL_KHR_blend_equation_advanced_coherent)
Decode and Encode before generateMipmap for srgb format textures on Windows: 634519
Applied Workarounds: decode_encode_srgb_for_generatemipmap
Delayed copy NV12 displays incorrect colors on NVIDIA drivers.: 728670
Applied Workarounds: disable_delayed_copy_nv12
Don't expose disjoint_timer_query extensions to WebGL: 808744
Native GpuMemoryBuffers have been disabled, either via about:flags or command line.
Disabled Features: native_gpu_memory_buffers
Viz service display compositor is not enabled by default.
Disabled Features: viz_display_compositor
Skia renderer is not used by default.
Disabled Features: skia_renderer
Skia deferred display list is not used by default.
Disabled Features: skia_deferred_display_list
Version Information
Data exported	2018-10-01T14:40:00.823Z
Browser version	OPR/56.0.3051.31
Operating system	Windows NT 10.0.17134
ANGLE commit id	unknown hash
2D graphics backend	Skia/69
Command Line	"C:\Program Files\Opera\56.0.3051.31\opera.exe" --ran-launcher --started-from-shortcut --flag-switches-begin --with-feature:dynamic-demuxer-selection --disable-features=SharedArrayBuffer,UseModernMediaControls --flag-switches-end --use-turbo2 --enable-quic
Driver Information
Initialization time	598
In-process GPU	false
Passthrough Command Decoder	false
Sandboxed	true
GPU0	VENDOR = 0x10de [Google Inc.], DEVICE= 0x1b81 [ANGLE (NVIDIA GeForce GTX 1070 Direct3D11 vs_5_0 ps_5_0)] *ACTIVE*
Optimus	false
AMD switchable	false
Desktop compositing	Aero Glass
Direct Composition	true
Supports overlays	false
Overlay capabilities
Diagonal Monitor Size of \\.\DISPLAY1	21.5"
Driver D3D12 feature level	Not supported
Driver Vulkan API version	Not supported
Driver vendor	NVIDIA
Driver version	23.21.13.8813
Driver date	10-27-2017
Pixel shader version	5.0
Vertex shader version	5.0
Max. MSAA samples	8
Machine model name	
Machine model version	
GL_VENDOR	Google Inc.
GL_RENDERER	ANGLE (NVIDIA GeForce GTX 1070 Direct3D11 vs_5_0 ps_5_0)
GL_VERSION	OpenGL ES 2.0 (ANGLE 2.1.0.unknown hash)
GL_EXTENSIONS	GL_ANGLE_client_arrays GL_ANGLE_depth_texture GL_ANGLE_explicit_context GL_ANGLE_explicit_context_gles1 GL_ANGLE_framebuffer_blit GL_ANGLE_framebuffer_multisample GL_ANGLE_instanced_arrays GL_ANGLE_lossy_etc_decode GL_ANGLE_pack_reverse_row_order GL_ANGLE_program_cache_control GL_ANGLE_request_extension GL_ANGLE_robust_client_memory GL_ANGLE_texture_compression_dxt3 GL_ANGLE_texture_compression_dxt5 GL_ANGLE_texture_usage GL_ANGLE_translated_shader_source GL_CHROMIUM_bind_generates_resource GL_CHROMIUM_bind_uniform_location GL_CHROMIUM_color_buffer_float_rgb GL_CHROMIUM_color_buffer_float_rgba GL_CHROMIUM_copy_compressed_texture GL_CHROMIUM_copy_texture GL_CHROMIUM_sync_query GL_EXT_blend_minmax GL_EXT_color_buffer_half_float GL_EXT_debug_marker GL_EXT_discard_framebuffer GL_EXT_disjoint_timer_query GL_EXT_draw_buffers GL_EXT_frag_depth GL_EXT_map_buffer_range GL_EXT_occlusion_query_boolean GL_EXT_read_format_bgra GL_EXT_robustness GL_EXT_sRGB GL_EXT_shader_texture_lod GL_EXT_texture_compression_dxt1 GL_EXT_texture_compression_s3tc_srgb GL_EXT_texture_filter_anisotropic GL_EXT_texture_format_BGRA8888 GL_EXT_texture_rg GL_EXT_texture_storage GL_EXT_unpack_subimage GL_KHR_debug GL_KHR_parallel_shader_compile GL_NV_EGL_stream_consumer_external GL_NV_fence GL_NV_pack_subimage GL_NV_pixel_buffer_object GL_OES_EGL_image GL_OES_EGL_image_external GL_OES_compressed_ETC1_RGB8_texture GL_OES_depth32 GL_OES_element_index_uint GL_OES_get_program_binary GL_OES_mapbuffer GL_OES_packed_depth_stencil GL_OES_rgb8_rgba8 GL_OES_standard_derivatives GL_OES_surfaceless_context GL_OES_texture_float GL_OES_texture_float_linear GL_OES_texture_half_float GL_OES_texture_half_float_linear GL_OES_texture_npot GL_OES_vertex_array_object OES_compressed_EAC_R11_signed_texture OES_compressed_EAC_R11_unsigned_texture OES_compressed_EAC_RG11_signed_texture OES_compressed_EAC_RG11_unsigned_texture OES_compressed_ETC2_RGB8_texture OES_compressed_ETC2_RGBA8_texture OES_compressed_ETC2_punchthroughA_RGBA8_texture OES_compressed_ETC2_punchthroughA_sRGB8_alpha_texture OES_compressed_ETC2_sRGB8_alpha8_texture OES_compressed_ETC2_sRGB8_texture
Disabled Extensions	GL_KHR_blend_equation_advanced GL_KHR_blend_equation_advanced_coherent
Disabled WebGL Extensions	EXT_disjoint_timer_query EXT_disjoint_timer_query_webgl2
Window system binding vendor	Google Inc. (adapter LUID: 000000000000a248)
Window system binding version	1.4 (ANGLE 2.1.0.unknown hash)
Window system binding extensions	EGL_EXT_create_context_robustness EGL_ANGLE_d3d_share_handle_client_buffer EGL_ANGLE_d3d_texture_client_buffer EGL_ANGLE_surface_d3d_texture_2d_share_handle EGL_ANGLE_query_surface_pointer EGL_ANGLE_window_fixed_size EGL_ANGLE_keyed_mutex EGL_ANGLE_surface_orientation EGL_ANGLE_direct_composition EGL_NV_post_sub_buffer EGL_KHR_create_context EGL_EXT_device_query EGL_KHR_image EGL_KHR_image_base EGL_KHR_gl_texture_2D_image EGL_KHR_gl_texture_cubemap_image EGL_KHR_gl_renderbuffer_image EGL_KHR_get_all_proc_addresses EGL_KHR_stream EGL_KHR_stream_consumer_gltexture EGL_NV_stream_consumer_gltexture_yuv EGL_ANGLE_flexible_surface_compatibility EGL_ANGLE_stream_producer_d3d_texture EGL_ANGLE_create_context_webgl_compatibility EGL_CHROMIUM_create_context_bind_generates_resource EGL_CHROMIUM_sync_control EGL_EXT_pixel_format_float EGL_KHR_surfaceless_context EGL_ANGLE_display_texture_share_group EGL_ANGLE_create_context_client_arrays EGL_ANGLE_program_cache_control EGL_ANGLE_robust_resource_initialization EGL_ANGLE_create_context_extensions_enabled
Direct rendering	Yes
Reset notification strategy	0x8252
GPU process crash count	0
Compositor Information
Tile Update Mode	One-copy
Partial Raster	Enabled
GpuMemoryBuffers Status
ATC	Software only
ATCIA	Software only
DXT1	Software only
DXT5	Software only
ETC1	Software only
R_8	Software only
R_16	Software only
RG_88	Software only
BGR_565	Software only
RGBA_4444	Software only
RGBX_8888	GPU_READ, SCANOUT
RGBA_8888	GPU_READ, SCANOUT
BGRX_8888	Software only
BGRX_1010102	Software only
RGBX_1010102	Software only
BGRA_8888	Software only
RGBA_F16	Software only
YVU_420	Software only
YUV_420_BIPLANAR	Software only
UYVY_422	Software only
Display(s) Information
Info	Display[2528732444] bounds=[0,0 1920x1080], workarea=[0,0 1920x1080], scale=1, external.
Color space information	{primaries_d50_referred: [[0.6510, 0.3380], [0.3180, 0.6120], [0.1510, 0.0650]], transfer:0.0777*x + 0.0000 if x < 0.0450 else (0.9478*x + 0.0521)**2.4000 + -0.0000, matrix:RGB, range:FULL}
Bits per color component	8
Bits per pixel	24
Video Acceleration Information
Decode h264 baseline	up to 4096x2304 pixels
Decode h264 baseline	up to 2304x4096 pixels
Decode h264 main	up to 4096x2304 pixels
Decode h264 main	up to 2304x4096 pixels
Decode h264 high	up to 4096x2304 pixels
Decode h264 high	up to 2304x4096 pixels
Decode vp8	up to 7680x4320 pixels
Decode vp8	up to 4320x7680 pixels
Decode vp9 profile0	up to 7680x4320 pixels
Decode vp9 profile0	up to 4320x7680 pixels
Decode vp9 profile1	up to 7680x4320 pixels
Decode vp9 profile1	up to 4320x7680 pixels
Decode vp9 profile2	up to 7680x4320 pixels
Decode vp9 profile2	up to 4320x7680 pixels
Decode vp9 profile3	up to 7680x4320 pixels
Decode vp9 profile3	up to 4320x7680 pixels
Encode h264 baseline	up to 3840x2176 pixels and/or 30.000 fps
Encode h264 main	up to 3840x2176 pixels and/or 30.000 fps
Encode h264 high	up to 3840x2176 pixels and/or 30.000 fps
Diagnostics
0
b3DAccelerationEnabled	true
b3DAccelerationExists	true
bAGPEnabled	true
bAGPExistenceValid	true
bAGPExists	true
bCanRenderWindow	true
bDDAccelerationEnabled	true
bDriverBeta	false
bDriverDebug	false
bDriverSigned	false
bDriverSignedValid	false
bNoHardware	false
dwBpp	32
dwDDIVersion	12
dwHeight	1080
dwRefreshRate	60
dwWHQLLevel	0
dwWidth	1920
iAdapter	0
lDriverSize	945072
lMiniVddSize	0
szAGPStatusEnglish	Enabled
szAGPStatusLocalized	Enabled
szChipType	GeForce GTX 1070
szD3DStatusEnglish	Enabled
szD3DStatusLocalized	Enabled
szDACType	Integrated RAMDAC
szDDIVersionEnglish	12
szDDIVersionLocalized	12
szDDStatusEnglish	Enabled
szDDStatusLocalized	Enabled
szDXVAHDEnglish	Supported
szDXVAModes	
szDescription	NVIDIA GeForce GTX 1070
szDeviceId	0x1B81
szDeviceIdentifier	{D7B71E3E-58C1-11CF-BF55-0C131BC2DA35}
szDeviceName	\\.\DISPLAY1
szDisplayMemoryEnglish	16269 MB
szDisplayMemoryLocalized	16269 MB
szDisplayModeEnglish	1920 x 1080 (32 bit) (60Hz)
szDisplayModeLocalized	1920 x 1080 (32 bit) (60Hz)
szDriverAssemblyVersion	23.21.13.8813
szDriverAttributes	Final Retail
szDriverDateEnglish	10/27/2017 2:00:00 AM
szDriverDateLocalized	10/27/2017 02:00:00
szDriverLanguageEnglish	English
szDriverLanguageLocalized	English
szDriverModelEnglish	WDDM 2.3
szDriverModelLocalized	WDDM 2.3
szDriverName	C:\WINDOWS\System32\DriverStore\FileRepository\nv_ref_pubwu.inf_amd64_2e7fa54192fe16d0\nvldumdx.dll,C:\WINDOWS\System32\DriverStore\FileRepository\nv_ref_pubwu.inf_amd64_2e7fa54192fe16d0\nvldumdx.dll,C:\WINDOWS\System32\DriverStore\FileRepository\nv_ref_pubwu.inf_amd64_2e7fa54192fe16d0\nvldumdx.dll,C:\WINDOWS\System32\DriverStore\FileRepository\nv_ref_pubwu.inf_amd64_2e7fa54192fe16d0\nvldumdx.dll
szDriverNodeStrongName	oem7.inf:0f066de361866ac3:Section136:23.21.13.8813:pci\ven_10de&dev_1b81
szDriverSignDate	Unknown
szDriverVersion	23.21.0013.8813
szKeyDeviceID	Enum\PCI\VEN_10DE&DEV_1B81&SUBSYS_33011462&REV_A1
szKeyDeviceKey	\Registry\Machine\System\CurrentControlSet\Control\Video\{DE4B625A-4D8E-11E8-B006-8CD7972A608E}\0000
szManufacturer	NVIDIA
szMiniVdd	unknown
szMiniVddDateEnglish	Unknown
szMiniVddDateLocalized	unknown
szMonitorMaxRes	Unknown
szMonitorName	Dell P2214H(Digital)
szNotesEnglish	No problems found.
szNotesLocalized	No problems found.
szOverlayEnglish	Supported
szRankOfInstalledDriver	00D12001
szRegHelpText	Unknown
szRevision	Unknown
szRevisionId	0x00A1
szSubSysId	0x33011462
szTestResultD3D7English	Not run
szTestResultD3D7Localized	Not run
szTestResultD3D8English	Not run
szTestResultD3D8Localized	Not run
szTestResultD3D9English	Not run
szTestResultD3D9Localized	Not run
szTestResultDDEnglish	Not run
szTestResultDDLocalized	Not run
szVdd	unknown
szVendorId	0x10DE
Log Messages
GpuProcessHostUIShim: The GPU process exited normally. Everything is okay.

Thank you for providing more feedback. Adding the requester to the cc list.

For more details visit https://www.chromium.org/issue-tracking/autotriage - Your friendly Sheriffbot

Reproduces on Mac.

Background Image regression from the changes made for M-69. Another one for the list though this seems to have a different cause than the others.