Reviewed by Kenneth Russell.

        copyTexSubImage2D shouldn't have undefined pixels
        https://bugs.webkit.org/show_bug.cgi?id=51559

        * html/canvas/WebGLRenderingContext.cpp:
        (WebCore::WebGLRenderingContext::copyTexImage2D): Refactor to share some code with copyTexSubImage2D through helper function clip2D.
        (WebCore::WebGLRenderingContext::copyTexSubImage2D): Initialize undefined pixels to 0.
        (WebCore::WebGLRenderingContext::validateTexFuncLevel): Seperate the validation of level from validateTexFuncParameters.
        (WebCore::WebGLRenderingContext::validateTexFuncParameters): Ditto.
        * html/canvas/WebGLRenderingContext.h:
        * html/canvas/WebGLTexture.cpp:
        (WebCore::WebGLTexture::getType): Expose the type of a texture.
        * html/canvas/WebGLTexture.h:
2011-01-06  Zhenyao Mo  <zmo@google.com>

        Reviewed by Kenneth Russell.

        copyTexSubImage2D shouldn't have undefined pixels
        https://bugs.webkit.org/show_bug.cgi?id=51559

        * fast/canvas/webgl/uninitialized-test-expected.txt:
        * fast/canvas/webgl/uninitialized-test.html: Add test cases for copyTexSubImage2D.


git-svn-id: http://svn.webkit.org/repository/webkit/trunk@75252 268f45cc-cd09-0410-ab3c-d52691b4dbfc