Bug 1379404 - Part 4. Prevent unnecessary AzureState copy in GlyphBufferAzure::Flush. r=mattwoodrow

~AzureState is expensive, especially in GlyphBufferAzure::Flush, which is a high
fan-in function.

MozReview-Commit-ID: 4JfjMje0Kgs

--HG--
extra : rebase_source : bbc2f06871d9bde9130ddb95d053d16a3f2a091d

gfx/thebes/gfxFont.cpp

@@ -1645,7 +1645,7 @@ private:
         buf.mGlyphs = mGlyphBuffer;
         buf.mNumGlyphs = mNumGlyphs;
 
-        gfxContext::AzureState state = mRunParams.context->CurrentState();
+        const gfxContext::AzureState &state = mRunParams.context->CurrentState();
         if (mRunParams.drawMode & DrawMode::GLYPH_FILL) {
             if (state.pattern || mFontParams.contextPaint) {
                 Pattern *pat;
@@ -1661,7 +1661,9 @@ private:
                 }
                 if (!fillPattern) {
                     if (state.pattern) {
-                        pat = state.pattern->GetPattern(mRunParams.dt,
+                        RefPtr<gfxPattern> statePattern =
+                          mRunParams.context->CurrentState().pattern;
+                        pat = statePattern->GetPattern(mRunParams.dt,
                                       state.patternTransformChanged ?
                                           &state.patternTransform : nullptr);
                     } else {

gfx/thebes/gfxPattern.cpp

@@ -106,7 +106,7 @@ gfxPattern::GetInverseMatrix() const
 
 Pattern*
 gfxPattern::GetPattern(const DrawTarget *aTarget,
-                       Matrix *aOriginalUserToDevice)
+                       const Matrix *aOriginalUserToDevice)
 {
   Matrix patternToUser = mPatternToUserSpace;
 

gfx/thebes/gfxPattern.h

@@ -48,7 +48,7 @@ public:
      * to the current transform.
      */
     mozilla::gfx::Pattern *GetPattern(const mozilla::gfx::DrawTarget *aTarget,
-                                      mozilla::gfx::Matrix *aOriginalUserToDevice = nullptr);
+                                      const mozilla::gfx::Matrix *aOriginalUserToDevice = nullptr);
     bool IsOpaque();
 
     // clamp, repeat, reflect