Update GraphicsContext3DOpenGLES.cpp and fix some issues to build with GLES.

Update GraphicsContext3DOpenGLES.cpp and fix some issues to build with GLES.
https://bugs.webkit.org/show_bug.cgi?id=83982

Patch by ChangSeok Oh <shivamidow@gmail.com> on 2012-04-16
Reviewed by Martin Robinson.

GL_BGRA is not defined in GLESv2, so it causes build-break at readRenderingResults.
To resolve this, a helper function readPixelsAndConvertToBGRAIfNecessary is added
in GC3DOpenGL.cpp & GC3DOpenGLES.cpp and it's used in GC3DOpenGLCommon.cpp.
And some other issues to build with GLES are gone with this patch.

No new tests, since no new feature.

* platform/graphics/GraphicsContext3D.h:
* platform/graphics/opengl/GraphicsContext3DOpenGL.cpp:
(WebCore::GraphicsContext3D::readPixelsAndConvertToBGRAIfNecessary):
(WebCore):
* platform/graphics/opengl/GraphicsContext3DOpenGLCommon.cpp:
(WebCore::GraphicsContext3D::readRenderingResults):
* platform/graphics/opengl/GraphicsContext3DOpenGLES.cpp:
(WebCore::GraphicsContext3D::readPixelsAndConvertToBGRAIfNecessary):
(WebCore):
(WebCore::GraphicsContext3D::reshapeFBOs):
(WebCore::GraphicsContext3D::resolveMultisamplingIfNecessary):

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@114268 268f45cc-cd09-0410-ab3c-d52691b4dbfc