Fix the crash of compressedTexImage3D for the WebGL2 conformance test page.

third_party/WebKit/Source/modules/webgl/WebGLTexture.cpp

Index: third_party/WebKit/Source/modules/webgl/WebGLTexture.cpp
diff --git a/third_party/WebKit/Source/modules/webgl/WebGLTexture.cpp b/third_party/WebKit/Source/modules/webgl/WebGLTexture.cpp
index 80d5bd122550a8930eb8e6535f6b55be582539e1..59634f0cd614176114d6753e75c3cd62e2589710 100644
--- a/third_party/WebKit/Source/modules/webgl/WebGLTexture.cpp
+++ b/third_party/WebKit/Source/modules/webgl/WebGLTexture.cpp
@@ -173,6 +173,10 @@ void WebGLTexture::setLevelInfo(GLenum target, GLint level, GLenum internalForma
     int index = mapTargetToIndex(target);
     if (index < 0)
         return;
+
+    if (level < 0 || level >= static_cast<GLint>(m_info[index].size()))
+        return;

[qiankun, 2015/11/23 06:19:00]

See the above comments. level should be validated already when entering
setLevelInfo. I think you should do level validation in
WebGL2RenderingContextBase::compressedTexImage3D. 

+
     m_info[index][level].setInfo(internalFormat, width, height, depth, type);
     update();
 }