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

third_party/WebKit/Source/modules/webgl/WebGL2RenderingContextBase.cpp

Index: third_party/WebKit/Source/modules/webgl/WebGL2RenderingContextBase.cpp
diff --git a/third_party/WebKit/Source/modules/webgl/WebGL2RenderingContextBase.cpp b/third_party/WebKit/Source/modules/webgl/WebGL2RenderingContextBase.cpp
index e8d9ee846d1ac3f0b0e95e7e5915a68a22b34ce5..c3d6afeae6f33c2ecb0f5df2d6a47d7156fd8726 100644
--- a/third_party/WebKit/Source/modules/webgl/WebGL2RenderingContextBase.cpp
+++ b/third_party/WebKit/Source/modules/webgl/WebGL2RenderingContextBase.cpp
@@ -929,6 +929,11 @@ void WebGL2RenderingContextBase::compressedTexImage3D(GLenum target, GLint level
     if (!tex)
         return;
 
+    if (!tex->isValidLevel(target, level)) {

[qiankun, 2015/11/23 12:06:53]

Please use validateTexFuncLevel(). You can refer the level validation in
WebGLRenderingContextBase::compressedTexImage2D().

+        synthesizeGLError(GL_INVALID_OPERATION, "compressedTexImage3D", "level does not valid");
+        return;
+    }
+
     if (tex->isImmutable()) {
         synthesizeGLError(GL_INVALID_OPERATION, "compressedTexImage3D", "attempted to modify immutable texture");
         return;