Revert "Store discard request on the opList and remove GrDiscardOp"

This reverts commit b681a0f1b0acebe36130fd463d14016d48295b97.

Reason for revert: Seems to be messing up some MacMini & Nexus7 bots
Original change's description:
> Store discard request on the opList and remove GrDiscardOp
> 
> Change-Id: Ic1f76bb91c16b23df1fe71c07a4d5ad5abf1dc26
> Reviewed-on: https://skia-review.googlesource.com/32640
> Reviewed-by: Brian Salomon <bsalomon@google.com>
> Commit-Queue: Robert Phillips <robertphillips@google.com>

TBR=egdaniel@google.com,bsalomon@google.com,robertphillips@google.com

Change-Id: I8a89fae7bb11791bd023d7444a074bb34d006fd0
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Reviewed-on: https://skia-review.googlesource.com/32704
Reviewed-by: Robert Phillips <robertphillips@google.com>
Commit-Queue: Robert Phillips <robertphillips@google.com>

1 files changed, 48 insertions, 0 deletions

diff --git a/src/gpu/ops/GrDiscardOp.h b/src/gpu/ops/GrDiscardOp.h
new file mode 100644
index 0000000000..d30aa5a8c5
--- /dev/null
+++ b/src/gpu/ops/GrDiscardOp.h
@@ -0,0 +1,48 @@
+/*
+ * Copyright 2015 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#ifndef GrDiscardOp_DEFINED
+#define GrDiscardOp_DEFINED
+
+#include "GrGpuCommandBuffer.h"
+#include "GrOp.h"
+#include "GrOpFlushState.h"
+#include "GrRenderTargetProxy.h"
+
+class GrDiscardOp final : public GrOp {
+public:
+    DEFINE_OP_CLASS_ID
+
+    static std::unique_ptr<GrOp> Make(GrRenderTargetProxy* proxy) {
+        return std::unique_ptr<GrOp>(new GrDiscardOp(proxy));
+    }
+
+    const char* name() const override { return "Discard"; }
+
+    SkString dumpInfo() const override {
+        SkString string;
+        string.append(INHERITED::dumpInfo());
+        return string;
+    }
+
+private:
+    GrDiscardOp(GrRenderTargetProxy* proxy) : INHERITED(ClassID()) {
+        this->makeFullScreen(proxy);
+    }
+
+    bool onCombineIfPossible(GrOp* that, const GrCaps& caps) override { return false; }
+
+    void onPrepare(GrOpFlushState*) override {}
+
+    void onExecute(GrOpFlushState* state) override {
+        state->commandBuffer()->discard();
+    }
+
+    typedef GrOp INHERITED;
+};
+
+#endif