[WEBGL] Rename WEBKIT_WEBGL_lose_context to WEBGL_lose_context.
https://bugs.webkit.org/show_bug.cgi?id=108694

Reviewed by Kenneth Russell.

WEBGL_lose_context is one of the community approved WebGL extension.
Hence remove the vendor prefix from WEBKIT_WEBGL_lose_context extension.
Spefication: http://www.khronos.org/registry/webgl/extensions/WEBGL_lose_context/

Source/WebCore:

Tests already exists, modified them to verify the change in extension name.

* bindings/js/JSWebGLRenderingContextCustom.cpp:
(WebCore::toJS):
* bindings/v8/custom/V8WebGLRenderingContextCustom.cpp:
(WebCore::toV8Object):
* html/canvas/WebGLExtension.h:
* html/canvas/WebGLLoseContext.cpp:
(WebCore::WebGLLoseContext::getName):
* html/canvas/WebGLRenderingContext.cpp:
(WebCore):
(WebCore::WebGLRenderingContext::getExtension):
(WebCore::WebGLRenderingContext::getSupportedExtensions):

LayoutTests:

* fast/canvas/webgl/WebGLContextEvent.html:
* fast/canvas/webgl/context-destroyed-crash.html:
* fast/canvas/webgl/context-lost-expected.txt:
* fast/canvas/webgl/context-lost-restored.html:
* fast/canvas/webgl/context-lost.html:
* platform/chromium-linux-x86/fast/canvas/webgl/context-lost-expected.txt:
* platform/chromium-linux/fast/canvas/webgl/context-lost-expected.txt:
* platform/chromium-mac/fast/canvas/webgl/context-lost-expected.txt:
* platform/chromium-win-xp/fast/canvas/webgl/context-lost-expected.txt:
* platform/chromium-win/fast/canvas/webgl/context-lost-expected.txt:
* platform/chromium/platform/chromium/virtual/gpu/fast/canvas/webgl/context-lost-expected.txt:


git-svn-id: http://svn.webkit.org/repository/webkit/trunk@141845 268f45cc-cd09-0410-ab3c-d52691b4dbfc