UserAgent: Mozilla/5.0 (Windows NT 6.1; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/57.0.2987.74 Safari/537.36

Example URL:
https://youtu.be/g2T80mtg-1c?t=6m46s

Steps to reproduce the problem:
1. Open any high-quality videos, such as this one: https://youtu.be/g2T80mtg-1c?t=6m46s make sure to change its quality to 1080p60
2. Start the playback.
3. Switch to another tab.
4. Switch back to the video tab.

What is the expected behavior?
The video should be playing as normal as soon as you switched back.

What went wrong?
While the audio is smooth throughout the process, the video takes quite a few seconds (more obvious on low-end computers [spec shown above] but still noticeable even with a relatively high-end desktop computer) to recover. It will pause or play in very low FPS in the first few seconds.

Did this work before? Yes 

Is it a problem with Flash or HTML5? HTML5

Does this work in other browsers? Yes

Chrome version: 57.0.2987.74  Channel: beta
OS Version: 6.1 (Windows 7, Windows Server 2008 R2)
Flash Version: Shockwave Flash 25.0 r0

Contents of chrome://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
Rasterization: Software only, hardware acceleration unavailable
Video Decode: Hardware accelerated
Video Encode: Hardware accelerated
VPx Video Decode: Software only, hardware acceleration unavailable
WebGL: Hardware accelerated
WebGL2: Hardware accelerated
Driver Bug Workarounds
clear_uniforms_before_first_program_use
decode_encode_srgb_for_generatemipmap
disable_direct_composition
disable_discard_framebuffer
disable_dxgi_zero_copy_video
disable_framebuffer_cmaa
exit_on_context_lost
force_cube_complete
msaa_is_slow
scalarize_vec_and_mat_constructor_args
texsubimage_faster_than_teximage
Problems Detected
VPx decoding isn't supported before Windows 10 anniversary update.: 616318
Disabled Features: accelerated_vpx_decode
GPU rasterization should only be enabled on NVIDIA Pascal and Maxwell, Intel Broadwell+, and AMD RX-R2 GPUs for now.: 643850
Disabled Features: gpu_rasterization
Accelerated VPx decoding is hanging on some videos.: 654111
Disabled Features: accelerated_vpx_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
On Intel GPUs MSAA performance is not acceptable for GPU rasterization: 527565
Applied Workarounds: msaa_is_slow
Framebuffer discarding can hurt performance on non-tilers: 570897
Applied Workarounds: disable_discard_framebuffer
Direct composition flashes black initially on Win <10: 588588
Applied Workarounds: disable_direct_composition
Zero copy DXGI video hangs on shutdown on Win < 8.1: 621190
Applied Workarounds: disable_dxgi_zero_copy_video
Limited enabling of Chromium GL_INTEL_framebuffer_CMAA: 535198
Applied Workarounds: disable_framebuffer_cmaa
Disable KHR_blend_equation_advanced until cc shaders are updated: 661715
Decode and Encode before generateMipmap for srgb format textures on Windows: 634519
Applied Workarounds: decode_encode_srgb_for_generatemipmap
Native GpuMemoryBuffers have been disabled, either via about:flags or command line.
Disabled Features: native_gpu_memory_buffers
Version Information
Data exported	2/27/2017, 10:57:11 AM
Chrome version	Chrome/57.0.2987.74
Operating system	Windows NT 6.1.7601 SP1
Software rendering list version	12.13
Driver bug list version	9.29
ANGLE commit id	c1a5d16e964a
2D graphics backend	Skia/57 e3917fd5ca950222facf027a73d95c8339bced54
Command Line Args	Files (x86)\Google\Chrome\Application\chrome.exe" --flag-switches-begin --disable-smooth-scrolling --flag-switches-end
Driver Information
Initialization time	39
In-process GPU	false
Passthrough Command Decoder	false
Sandboxed	false
GPU0	VENDOR = 0x8086, DEVICE= 0x0116
Optimus	false
AMD switchable	false
Desktop compositing	Aero Glass
Diagonal Monitor Size of \\.\DISPLAY1	21.9"
Diagonal Monitor Size of \\.\DISPLAY1	13.9"
Diagonal Monitor Size of \\.\DISPLAY2	13.9"
Driver vendor	Advanced Micro Devices, Inc.
Driver version	8.910.0.0
Driver date	10-13-2011
Pixel shader version	4.1
Vertex shader version	4.1
Max. MSAA samples	4
Machine model name	
Machine model version	
GL_VENDOR	Google Inc.
GL_RENDERER	ANGLE (Intel(R) HD Graphics Family Direct3D11 vs_4_1 ps_4_1)
GL_VERSION	OpenGL ES 3.0 (ANGLE 2.1.0.c1a5d16e964a)
GL_EXTENSIONS	GL_ANGLE_depth_texture 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_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_copy_compressed_texture GL_CHROMIUM_copy_texture GL_CHROMIUM_sync_query GL_EXT_blend_minmax GL_EXT_color_buffer_float 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_norm16 GL_EXT_texture_rg GL_EXT_texture_storage GL_EXT_unpack_subimage GL_KHR_debug 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_EGL_image_external_essl3 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_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
Disabled Extensions	GL_KHR_blend_equation_advanced GL_KHR_blend_equation_advanced_coherent
Window system binding vendor	Google Inc. (adapter LUID: 000000000000883e)
Window system binding version	1.4 (ANGLE 2.1.0.c1a5d16e964a)
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_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_create_context_webgl_compatibility EGL_CHROMIUM_create_context_bind_generates_resource
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
RG_88	Software only
BGR_565	Software only
RGBA_4444	Software only
RGBX_8888	Software only
RGBA_8888	Software only
BGRX_8888	Software only
BGRA_8888	Software only
YVU_420	Software only
YUV_420_BIPLANAR	Software only
UYVY_422	Software only
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	10
dwHeight	1050
dwRefreshRate	59
dwWHQLLevel	0
dwWidth	1680
iAdapter	0
lDriverSize	8312320
lMiniVddSize	0
szAGPStatusEnglish	Enabled
szAGPStatusLocalized	Enabled
szChipType	Intel(R) HD Graphics Family
szD3DStatusEnglish	Enabled
szD3DStatusLocalized	Enabled
szDACType	Internal
szDDIVersionEnglish	10.1
szDDIVersionLocalized	10.1
szDDStatusEnglish	Enabled
szDDStatusLocalized	Enabled
szDXVAHDEnglish	Supported
szDXVAModes	ModeMPEG2_A ModeMPEG2_C ModeWMV9_C ModeVC1_C
szDescription	Intel(R) HD Graphics Family
szDeviceId	0x0116
szDeviceIdentifier	{D7B78E66-4256-11CF-417A-7436A9C2C535}
szDeviceName	\\.\DISPLAY1
szDisplayMemoryEnglish	1696 MB
szDisplayMemoryLocalized	1696 MB
szDisplayModeEnglish	1680 x 1050 (32 bit) (59Hz)
szDisplayModeLocalized	1680 x 1050 (32 bit) (59Hz)
szDriverAssemblyVersion	8.910.0.0
szDriverAttributes	Final Retail
szDriverDateEnglish	8/31/2011 12:53:18
szDriverDateLocalized	8/31/2011 12:53:18 PM
szDriverLanguageEnglish	English
szDriverLanguageLocalized	English
szDriverModelEnglish	WDDM 1.1
szDriverModelLocalized	WDDM 1.1
szDriverName	igdumd64.dll,igd10umd64.dll,igd10umd64.dll,igdumdx32,igd10umd32,igd10umd32
szDriverNodeStrongName	oem43.inf:ATI.Mfg.NTamd64.6.1:iSNBM0:8.910.0.0:pci\ven_8086&dev_0116&subsys_167e103c
szDriverSignDate	
szDriverVersion	8.15.0010.2509
szKeyDeviceID	Enum\PCI\VEN_8086&DEV_0116&SUBSYS_167E103C&REV_09
szKeyDeviceKey	\Registry\Machine\System\CurrentControlSet\Control\Video\{75EC101F-15AA-4339-A31A-40C00675FAAD}\0000
szManufacturer	Advanced Micro Devices, Inc.
szMiniVdd	n/a
szMiniVddDateEnglish	n/a
szMiniVddDateLocalized	n/a
szMonitorMaxRes	
szMonitorName	通用即插即用监视器
szNotesEnglish	No problems found.
szNotesLocalized	No problems found.
szOverlayEnglish	Supported
szRankOfInstalledDriver	00E60001
szRegHelpText	
szRevision	
szRevisionId	0x0009
szSubSysId	0x167E103C
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	n/a
szVendorId	0x8086
Log Messages
GpuProcessHostUIShim: The GPU process exited normally. Everything is okay.

It only starts in recent few months but I'm not sure about the exact regression window.