Revert r3054 for failing tests



git-svn-id: http://skia.googlecode.com/svn/trunk@3055 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/src/gpu/GrDrawTarget.cpp b/src/gpu/GrDrawTarget.cpp
index fa266d1..be6bd0a 100644
--- a/src/gpu/GrDrawTarget.cpp
+++ b/src/gpu/GrDrawTarget.cpp
@@ -885,10 +885,8 @@
 
     // When coeffs are (0,1) there is no reason to draw at all, unless
     // stenciling is enabled. Having color writes disabled is effectively
-    // (0,1). The same applies when coverage is known to be 0.
-    if ((kZero_BlendCoeff == *srcCoeff && dstCoeffIsOne) ||
-        (!(layout & kCoverage_VertexLayoutBit) && 
-         0 == drawState.getCoverage())) {
+    // (0,1).
+    if ((kZero_BlendCoeff == *srcCoeff && dstCoeffIsOne)) {
         if (drawState.getStencil().doesWrite()) {
             return kDisableBlend_BlendOptFlag |
                    kEmitTransBlack_BlendOptFlag;
@@ -897,10 +895,8 @@
         }
     }
 
-    // check for coverage due to constant coverage, per-vertex coverage,
-    // edge aa or coverage texture stage
+    // check for coverage due to edge aa or coverage texture stage
     bool hasCoverage = forceCoverage ||
-                       0xffffffff != drawState.getCoverage() || 
                        drawState.getNumAAEdges() > 0 ||
                        (layout & kCoverage_VertexLayoutBit) ||
                        (layout & kEdge_VertexLayoutBit);