Bug 1389010, part 2 - Move an early return in nsCSSBorderRenderer::DrawBorders up to avoid unnecessary work. r=dholbert

MozReview-Commit-ID: AfuBCfYs3S1

layout/painting/nsCSSRenderingBorders.cpp

@@ -3214,6 +3214,14 @@ nsCSSBorderRenderer::DrawBorders()
     return;
   }
 
+  bool allBordersSameWidth = AllBordersSameWidth();
+
+  if (allBordersSameWidth && mBorderWidths[0] == 0.0) {
+    // Some of the allBordersSameWidth codepaths depend on the border
+    // width being greater than zero.
+    return;
+  }
+
   AutoRestoreTransform autoRestoreTransform;
   Matrix mat = mDrawTarget->GetTransform();
 
@@ -3241,14 +3249,6 @@ nsCSSBorderRenderer::DrawBorders()
     mInnerRect.Round();
   }
 
-  bool allBordersSameWidth = AllBordersSameWidth();
-
-  if (allBordersSameWidth && mBorderWidths[0] == 0.0) {
-    // Some of the allBordersSameWidth codepaths depend on the border
-    // width being greater than zero.
-    return;
-  }
-
   // Initial values only used when the border colors/widths are all the same:
   ColorPattern color(ToDeviceColor(mBorderColors[eSideTop]));
   StrokeOptions strokeOptions(mBorderWidths[eSideTop]); // stroke width