Change GR_COMPRESS_ALPHA_MASK from compile-time flag to run-time flag

src/gpu/GrContext.cpp

Index: src/gpu/GrContext.cpp
diff --git a/src/gpu/GrContext.cpp b/src/gpu/GrContext.cpp
index 96380bdfe66995a73532acbd8999a279507673d4..5a2a2b658480a7b304b0c3555cec6c7657c2eeea 100755
--- a/src/gpu/GrContext.cpp
+++ b/src/gpu/GrContext.cpp
@@ -84,9 +84,20 @@ private:
     GrContext* fContext;
 };
 
-GrContext* GrContext::Create(GrBackend backend, GrBackendContext backendContext) {
+GrContext::Options::Options() 
+    : fDrawPathToCompressedTexture(false)
+{ }
+
+GrContext* GrContext::Create(GrBackend backend, GrBackendContext backendContext,
+                             const Options* opts) {
     GrContext* context = SkNEW(GrContext);
-    if (context->init(backend, backendContext)) {
+
+    Options defaultOpts;
+    if (NULL == opts) {
+        opts = &defaultOpts;
+    }
+
+    if (context->init(backend, backendContext, *opts)) {
         return context;
     } else {
         context->unref();
@@ -112,7 +123,7 @@ GrContext::GrContext() {
     fMaxTextureSizeOverride = 1 << 20;
 }
 
-bool GrContext::init(GrBackend backend, GrBackendContext backendContext) {
+bool GrContext::init(GrBackend backend, GrBackendContext backendContext, const Options& opts) {
     SkASSERT(NULL == fGpu);
 
     fGpu = GrGpu::Create(backend, backendContext, this);
@@ -140,6 +151,8 @@ bool GrContext::init(GrBackend backend, GrBackendContext backendContext) {
 
     this->setupDrawBuffer();
 
+    fSupportsDrawPathToCompressed = opts.fDrawPathToCompressedTexture;
+
     return true;
 }
 
@@ -607,6 +620,14 @@ int GrContext::getMaxSampleCount() const {
     return fGpu->caps()->maxSampleCount();
 }
 
+bool GrContext::supportsDrawPathToCompressedTexture() const {
+    if (!(fGpu->caps()->compressedTexSubImageSupport())) {
+        return false;
+    }
+
+    return fSupportsDrawPathToCompressed;
+}
+
 ///////////////////////////////////////////////////////////////////////////////
 
 GrTexture* GrContext::wrapBackendTexture(const GrBackendTextureDesc& desc) {