Add dual source blending support for proper blending with coverage.

Review URL: http://codereview.appspot.com/4535088/



git-svn-id: http://skia.googlecode.com/svn/trunk@1390 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/gpu/src/GrGpuGLFixed.cpp b/gpu/src/GrGpuGLFixed.cpp
index e197a82..65229dc 100644
--- a/gpu/src/GrGpuGLFixed.cpp
+++ b/gpu/src/GrGpuGLFixed.cpp
@@ -57,6 +57,7 @@
 
 GrGpuGLFixed::GrGpuGLFixed() {
     f4X4DownsampleFilterSupport = false;
+    fDualSourceBlendingSupport = false;
 }
 
 GrGpuGLFixed::~GrGpuGLFixed() {
@@ -136,8 +137,8 @@
     }
 
     if (GR_GL_SUPPORT_ES1) {
-        if (BlendCoefReferencesConstant(fCurrDrawState.fSrcBlend) ||
-            BlendCoefReferencesConstant(fCurrDrawState.fDstBlend)) {
+        if (BlendCoeffReferencesConstant(fCurrDrawState.fSrcBlend) ||
+            BlendCoeffReferencesConstant(fCurrDrawState.fDstBlend)) {
             unimpl("ES1 doesn't support blend constant");
             return false;
         }
@@ -147,6 +148,8 @@
         return false;
     }
 
+    this->flushBlend(type, fCurrDrawState.fSrcBlend, fCurrDrawState.fDstBlend);
+
     if (fDirtyFlags.fRenderTargetChanged) {
         flushProjectionMatrix();
     }