https://bugs.webkit.org/show_bug.cgi?id=104955

Reviewed by Julien Chaffraix.

Source/WebCore: 

LayoutUnit::operator/ currently does not clamp values and
instead overflows when given a value greater than INT_MAX or
less than INT_MIN. 

Test: TestWebKitAPI/Tests/WebCore/LayoutUnit.cpp

* platform/LayoutUnit.h:
(WebCore::operator/):
Clamp value if SATURATED_LAYOUT_ARITHMETIC is enabled.

Tools: 

Add tests for LayoutUnit.

* TestWebKitAPI/CMakeLists.txt:
* TestWebKitAPI/ForwardingHeaders: Added.
* TestWebKitAPI/ForwardingHeaders/WebCore: Added.
* TestWebKitAPI/ForwardingHeaders/WebCore/LayoutUnit.h: Added.
* TestWebKitAPI/TestWebKitAPI.gyp/TestWebKitAPI.gyp:
* TestWebKitAPI/TestWebKitAPI.gypi:
* TestWebKitAPI/TestWebKitAPI.xcodeproj/project.pbxproj:
* TestWebKitAPI/Tests/WebCore/LayoutUnit.cpp: Added.
(TestWebKitAPI):
(TestWebKitAPI::TEST):
* TestWebKitAPI/win/TestWebKitAPI.vcproj:


git-svn-id: http://svn.webkit.org/repository/webkit/trunk@137924 268f45cc-cd09-0410-ab3c-d52691b4dbfc