Fix the crash problem on WebGL2 conformance test of negative state api.

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..948e7b3c2ffa3f907b9942f8a66587e0969f9768 100644
--- a/third_party/WebKit/Source/modules/webgl/WebGL2RenderingContextBase.cpp
+++ b/third_party/WebKit/Source/modules/webgl/WebGL2RenderingContextBase.cpp
@@ -2211,8 +2211,10 @@ String WebGL2RenderingContextBase::getActiveUniformBlockName(WebGLProgram* progr
         return String();
     }
     OwnPtr<GLchar[]> name = adoptArrayPtr(new GLchar[maxNameLength]);
-    GLsizei length;
+
+    GLsizei length = 0;
     webContext()->getActiveUniformBlockName(objectOrZero(program), uniformBlockIndex, maxNameLength, &length, name.get());
+
     return String(name.get(), length);
 }