Bug 613350 - Pass 2 more WebGL draw-test - r=vladimir a=joe

content/canvas/src/WebGLContextGL.cpp

@@ -1047,6 +1047,10 @@ WebGLContext::DrawArrays(GLenum mode, WebGLint first, WebGLsizei count)
     if (first < 0 || count < 0)
         return ErrorInvalidValue("DrawArrays: negative first or count");
 
+    // If count is 0, there's nothing to do.
+    if (count == 0)
+        return NS_OK;
+
     // If there is no current program, this is silently ignored.
     // Any checks below this depend on a program being available.
     if (!mCurrentProgram)
@@ -1060,10 +1064,6 @@ WebGLContext::DrawArrays(GLenum mode, WebGLint first, WebGLsizei count)
     if (!ValidateBuffers(checked_firstPlusCount.value()))
         return ErrorInvalidOperation("DrawArrays: bound vertex attribute buffers do not have sufficient size for given first and count");
 
-    // If count is 0, there's nothing to do.
-    if (count == 0)
-        return NS_OK;
-
     MakeContextCurrent();
 
     if (mBoundFramebuffer && !mBoundFramebuffer->CheckAndInitializeRenderbuffers())
@@ -1091,6 +1091,10 @@ WebGLContext::DrawElements(WebGLenum mode, WebGLsizei count, WebGLenum type, Web
     if (count < 0 || byteOffset < 0)
         return ErrorInvalidValue("DrawElements: negative count or offset");
 
+    // If count is 0, there's nothing to do.
+    if (count == 0)
+        return NS_OK;
+
     CheckedUint32 checked_byteCount;
 
     if (type == LOCAL_GL_UNSIGNED_SHORT) {
@@ -1143,10 +1147,6 @@ WebGLContext::DrawElements(WebGLenum mode, WebGLsizei count, WebGLenum type, Web
                                      "size for given indices from the bound element array");
     }
 
-    // If count is 0, there's nothing to do.
-    if (count == 0)
-        return NS_OK;
-
     MakeContextCurrent();
 
     if (mBoundFramebuffer && !mBoundFramebuffer->CheckAndInitializeRenderbuffers())