The ios-simulator builder has some problems with base after adding support for jumbo there. Maybe similar to the cross compiling problems we had with nacl. 
Failing build: https://build.chromium.org/p/tryserver.chromium.mac/builders/ios-simulator/builds/320643

[6939/33986] LINK obj/base/x64/base_perftests
FAILED: obj/base/x64/base_perftests 
export DEVELOPER_DIR=/b/build/slave/ios-simulator/build/src/build/ios_files/Xcode.app;  TOOL_VERSION=1504925436 ../../build/toolchain/mac/linker_driver.py ../../third_party/llvm-build/Release+Asserts/bin/clang++  -Xlinker -rpath -Xlinker @executable_path/Frameworks -Xlinker -objc_abi_version -Xlinker 2 -Xlinker -sectcreate -Xlinker __TEXT -Xlinker __entitlements -Xlinker obj/base/base_perftests.xcent -arch x86_64 -Werror -isysroot /b/build/slave/ios-simulator/build/src/build/ios_files/Xcode.app/Contents/Developer/Platforms/iPhoneSimulator.platform/Developer/SDKs/iPhoneSimulator11.0.sdk -stdlib=libc++ -mios-simulator-version-min=9.0 -Wl,-ObjC -o "obj/base/x64/base_perftests" -Wl,-filelist,"obj/base/x64/base_perftests.rsp"  -framework UIKit -framework CoreFoundation -framework CoreGraphics -framework CoreText -framework Foundation
Undefined symbols for architecture x86_64:
  "base::allocator::g_replaced_default_zone", referenced from:
      base::allocator::IsAllocatorInitialized() in libbase.a(base_jumbo_1.o)
ld: symbol(s) not found for architecture x86_64
clang: error: linker command failed with exit code 1 (use -v to see invocation)
Traceback (most recent call last):
  File "../../build/toolchain/mac/linker_driver.py", line 229, in <module>
    Main(sys.argv)
  File "../../build/toolchain/mac/linker_driver.py", line 79, in Main
    subprocess.check_call(compiler_driver_args)
  File "/System/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/subprocess.py", line 540, in check_call
    raise CalledProcessError(retcode, cmd)
subprocess.CalledProcessError: Command '['../../third_party/llvm-build/Release+Asserts/bin/clang++', '-Xlinker', '-rpath', '-Xlinker', '@executable_path/Frameworks', '-Xlinker', '-objc_abi_version', '-Xlinker', '2', '-Xlinker', '-sectcreate', '-Xlinker', '__TEXT', '-Xlinker', '__entitlements', '-Xlinker', 'obj/base/base_perftests.xcent', '-arch', 'x86_64', '-Werror', '-isysroot', '/b/build/slave/ios-simulator/build/src/build/ios_files/Xcode.app/Contents/Developer/Platforms/iPhoneSimulator.platform/Developer/SDKs/iPhoneSimulator11.0.sdk', '-stdlib=libc++', '-mios-simulator-version-min=9.0', '-Wl,-ObjC', '-o', 'obj/base/x64/base_perftests', '-Wl,-filelist,obj/base/x64/base_perftests.rsp', '-framework', 'UIKit', '-framework', 'CoreFoundation', '-framework', 'CoreGraphics', '-framework', 'CoreText', '-framework', 'Foundation']' returned non-zero exit status 1
[6940/33986] LIBTOOL-STATIC obj/ui/gfx/range/librange.a
[6941/33986] ACTION //ui/gfx/mojo:mojo__generator(//build/toolchain/mac:ios_clang_x64)
[6942/33986] LINK obj/base/x64/base_i18n_perftests
FAILED: obj/base/x64/base_i18n_perftests 
export DEVELOPER_DIR=/b/build/slave/ios-simulator/build/src/build/ios_files/Xcode.app;  TOOL_VERSION=1504925436 ../../build/toolchain/mac/linker_driver.py ../../third_party/llvm-build/Release+Asserts/bin/clang++  -Xlinker -rpath -Xlinker @executable_path/Frameworks -Xlinker -objc_abi_version -Xlinker 2 -Xlinker -sectcreate -Xlinker __TEXT -Xlinker __entitlements -Xlinker obj/base/base_i18n_perftests.xcent -arch x86_64 -Werror -isysroot /b/build/slave/ios-simulator/build/src/build/ios_files/Xcode.app/Contents/Developer/Platforms/iPhoneSimulator.platform/Developer/SDKs/iPhoneSimulator11.0.sdk -stdlib=libc++ -mios-simulator-version-min=9.0 -Wl,-ObjC -o "obj/base/x64/base_i18n_perftests" -Wl,-filelist,"obj/base/x64/base_i18n_perftests.rsp"  -framework UIKit -framework CoreFoundation -framework CoreGraphics -framework CoreText -framework Foundation
Undefined symbols for architecture x86_64:
  "base::allocator::g_replaced_default_zone", referenced from:
      base::allocator::IsAllocatorInitialized() in libbase.a(base_jumbo_1.o)
ld: symbol(s) not found for architecture x86_64
clang: error: linker command failed with exit code 1 (use -v to see invocation)
Traceback (most recent call last):
  File "../../build/toolchain/mac/linker_driver.py", line 229, in <module>
    Main(sys.argv)
  File "../../build/toolchain/mac/linker_driver.py", line 79, in Main
    subprocess.check_call(compiler_driver_args)
  File "/System/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/subprocess.py", line 540, in check_call
    raise CalledProcessError(retcode, cmd)
subprocess.CalledProcessError: Command '['../../third_party/llvm-build/Release+Asserts/bin/clang++', '-Xlinker', '-rpath', '-Xlinker', '@executable_path/Frameworks', '-Xlinker', '-objc_abi_version', '-Xlinker', '2', '-Xlinker', '-sectcreate', '-Xlinker', '__TEXT', '-Xlinker', '__entitlements', '-Xlinker', 'obj/base/base_i18n_perftests.xcent', '-arch', 'x86_64', '-Werror', '-isysroot', '/b/build/slave/ios-simulator/build/src/build/ios_files/Xcode.app/Contents/Developer/Platforms/iPhoneSimulator.platform/Developer/SDKs/iPhoneSimulator11.0.sdk', '-stdlib=libc++', '-mios-simulator-version-min=9.0', '-Wl,-ObjC', '-o', 'obj/base/x64/base_i18n_perftests', '-Wl,-filelist,obj/base/x64/base_i18n_perftests.rsp', '-framework', 'UIKit', '-framework', 'CoreFoundation', '-framework', 'CoreGraphics', '-framework', 'CoreText', '-framework', 'Foundation']' returned non-zero exit status 1

ios-simulator is not an important platform for most developers so the right thing to do might be to not even try to support jumbo for it.