Associate URLs with GraphicsContext3D instances created for WebGL
https://bugs.webkit.org/show_bug.cgi?id=103793

Reviewed by Adam Barth.

Source/Platform:

* chromium/public/WebGraphicsContext3D.h:
(Attributes):
    Add top document's URL to context creation attributes.

Source/WebCore:

Pass down the URL of the topmost frame's document creating the
WebGL context to the platform layer through
GraphicsContext3D::Attributes.

Not feasible to write a layout test for this change; has no
user-visible effect. Tested manually with failure injection in
Chromium port.

* html/canvas/WebGLRenderingContext.cpp:
(WebCore):
(WebCore::WebGLRenderingContext::create):
    Pass top document's URL in context creation attributes.
* platform/chromium/support/GraphicsContext3DChromium.cpp:
(WebCore::GraphicsContext3D::create):
    Pass URL through WebKit API.
* platform/graphics/GraphicsContext3D.h:
(Attributes):
    Add top document's URL to context creation attributes.

git-svn-id: https://svn.webkit.org/repository/webkit/trunk/Source/Platform/chromium/public@136907 268f45cc-cd09-0410-ab3c-d52691b4dbfc