Enable vertexless shading when path rendering is supported

src/gpu/gl/GrGLShaderBuilder.cpp

Index: src/gpu/gl/GrGLShaderBuilder.cpp
diff --git a/src/gpu/gl/GrGLShaderBuilder.cpp b/src/gpu/gl/GrGLShaderBuilder.cpp
index f73520c363f268a7666689d2a4b26404afbcaea0..0d09606ddcfbbb7d9bdc351ecd4a817c1a71a2e4 100644
--- a/src/gpu/gl/GrGLShaderBuilder.cpp
+++ b/src/gpu/gl/GrGLShaderBuilder.cpp
@@ -102,12 +102,21 @@ GrGLShaderBuilder::GrGLShaderBuilder(const GrGLContextInfo& ctxInfo,
     , fFSInputs(kVarsPerBlock)
     , fFSOutputs(kMaxFSOutputs)
     , fSetupFragPosition(false)
-    , fTopLeftFragPosRead(kTopLeftFragPosRead_FragPosKey == desc.getHeader().fFragPosKey) {
+    , fTopLeftFragPosRead(kTopLeftFragPosRead_FragPosKey == desc.getHeader().fFragPosKey)
+    , fNumTexGenUnits(0) {
 
     const GrGLProgramDesc::KeyHeader& header = desc.getHeader();
 
-    // TODO: go vertexless when possible.
-    fVertexBuilder.reset(SkNEW_ARGS(VertexBuilder, (this, desc)));
+    // We only go without a vertex shader if every effect supports vertexless mode, the context
+    // has fixed function/path rendering support, and position is the only vertex attribute.
+    if (hasVertexShaderEffects ||
+        !ctxInfo.caps()->fixedFunctionSupport() ||
+        !ctxInfo.caps()->pathStencilingSupport() ||
+        -1 != header.fLocalCoordAttributeIndex ||
+        -1 != header.fColorAttributeIndex ||
+        -1 != header.fCoverageAttributeIndex) {
+        fVertexBuilder.reset(SkNEW_ARGS(VertexBuilder, (this, desc)));
+    }
 
     // Emit code to read the dst copy textue if necessary.
     if (kNoDstRead_DstReadKey != header.fDstReadKey &&
@@ -434,6 +443,23 @@ void GrGLShaderBuilder::fsEmitFunction(GrSLType returnType,
     fFSFunctions.append("}\n\n");
 }
 
+void GrGLShaderBuilder::addTexGenUnit(GrSLType type,
+                                      SkString* fsInName,
+                                      int* unitIdx,
+                                      int* numComponents)
+{

[bsalomon, 2013/09/10 13:51:06]

style nit: { up on prev line

+    const int index = fNumTexGenUnits++;
+    if (fsInName) {
+        fsInName->printf("%s(gl_TexCoord[%u])", GrGLSLTypeString(type), index);
+    }
+    if (unitIdx) {
+        *unitIdx = index;
+    }
+    if (numComponents) {
+        *numComponents = GrSLTypeToVecLength(type);
+    }
+}
+
 namespace {
 
 inline void append_default_precision_qualifier(GrGLShaderVar::Precision p,