Bug 1088071, part 1 - Wrap the callers of the final nsRenderingContext::DrawString method up in a new nsLayoutUtils::DrawUniDirString method. r=jfkthame

layout/base/nsLayoutUtils.cpp

@@ -4649,10 +4649,19 @@ nsLayoutUtils::DrawString(const nsIFrame*       aFrame,
   if (NS_FAILED(rv))
   {
     aContext->SetTextRunRTL(false);
-    aContext->DrawString(aString, aLength, aPoint.x, aPoint.y);
+    DrawUniDirString(aString, aLength, aPoint, *aContext);
   }
 }
 
+void
+nsLayoutUtils::DrawUniDirString(const char16_t* aString,
+                                uint32_t aLength,
+                                nsPoint aPoint,
+                                nsRenderingContext& aContext)
+{
+  aContext.DrawString(aString, aLength, aPoint.x, aPoint.y);
+}
+
 nscoord
 nsLayoutUtils::GetStringWidth(const nsIFrame*      aFrame,
                               nsRenderingContext* aContext,

layout/base/nsLayoutUtils.h

@@ -1324,6 +1324,11 @@ public:
                          nsPoint               aPoint,
                          nsStyleContext*       aStyleContext = nullptr);
 
+  static void DrawUniDirString(const char16_t* aString,
+                               uint32_t aLength,
+                               nsPoint aPoint,
+                               nsRenderingContext& aContext);
+
   static nscoord GetStringWidth(const nsIFrame*      aFrame,
                                 nsRenderingContext* aContext,
                                 const char16_t*     aString,

layout/generic/nsImageFrame.cpp

@@ -1123,8 +1123,11 @@ nsImageFrame::DisplayAltText(nsPresContext*      aPresContext,
                                          aRenderingContext,
                                          aRect.x, y + maxAscent);
     }
-    if (NS_FAILED(rv))
-      aRenderingContext.DrawString(str, maxFit, aRect.x, y + maxAscent);
+    if (NS_FAILED(rv)) {
+      nsLayoutUtils::DrawUniDirString(str, maxFit,
+                                      nsPoint(aRect.x, y + maxAscent),
+                                      aRenderingContext);
+    }
 
     // Move to the next line
     str += maxFit;

layout/mathml/nsMathMLContainerFrame.cpp

@@ -110,8 +110,10 @@ void nsDisplayMathMLError::Paint(nsDisplayListBuilder* aBuilder,
   aCtx->ThebesContext()->SetColor(NS_RGB(255,255,255));
   nscoord ascent = aCtx->FontMetrics()->MaxAscent();
   NS_NAMED_LITERAL_STRING(errorMsg, "invalid-markup");
-  aCtx->DrawString(errorMsg.get(), uint32_t(errorMsg.Length()),
-                   pt.x, pt.y+ascent);
+  nsLayoutUtils::DrawUniDirString(errorMsg.get(),
+                                  uint32_t(errorMsg.Length()),
+                                  nsPoint(pt.x, pt.y + ascent),
+                                  *aCtx);
 }
 
 /* /////////////