Add new GM to directly exercise perspective bitmap drawing

src/gpu/GrDrawContext.cpp

Index: src/gpu/GrDrawContext.cpp
diff --git a/src/gpu/GrDrawContext.cpp b/src/gpu/GrDrawContext.cpp
index b11518f018fe89d86444785b053291c6ebc1b7e3..3942647a7381ec6288d5e439642cf9c0f36f01a8 100644
--- a/src/gpu/GrDrawContext.cpp
+++ b/src/gpu/GrDrawContext.cpp
@@ -274,7 +274,6 @@ void GrDrawContext::drawRect(GrRenderTarget* rt,
     // The fill path can handle rotation but not skew
     // The stroke path needs the rect to remain axis aligned (no rotation or skew)
     // None of our draw rect calls can handle perspective yet
-    SkASSERT(!viewMatrix.hasPerspective());

[joshualitt, 2015/09/02 17:37:20]

Could we move this to line 281? maybe its not necessary.

[robertphillips, 2015/09/03 15:25:31]

Done.

     bool canApplyAA = width >=0 ? viewMatrix.rectStaysRect() : viewMatrix.preservesRightAngles();
 
     if (needAA && canApplyAA) {