4 files changed, 16 insertions, 2 deletions
diff --git a/src/gpu/gl/GrGLCaps.cpp b/src/gpu/gl/GrGLCaps.cpp
index 8e6c3e2d23..60c0dfaf10 100644
--- a/src/gpu/gl/GrGLCaps.cpp
+++ b/src/gpu/gl/GrGLCaps.cpp
@@ -48,6 +48,7 @@ void GrGLCaps::reset() {
     fIsCoreProfile = false;
     fFixedFunctionSupport = false;
     fDiscardFBSupport = false;
+    fFullClearIsFree = false;
 }
 
 GrGLCaps::GrGLCaps(const GrGLCaps& caps) : GrDrawTargetCaps() {
@@ -84,6 +85,7 @@ GrGLCaps& GrGLCaps::operator = (const GrGLCaps& caps) {
     fIsCoreProfile = caps.fIsCoreProfile;
     fFixedFunctionSupport = caps.fFixedFunctionSupport;
     fDiscardFBSupport = caps.fDiscardFBSupport;
+    fFullClearIsFree = caps.fFullClearIsFree;
 
     return *this;
 }
@@ -224,6 +226,10 @@ void GrGLCaps::init(const GrGLContextInfo& ctxInfo, const GrGLInterface* gli) {
 
     fDiscardFBSupport = ctxInfo.hasExtension("GL_EXT_discard_framebuffer");
 
+    if (kARM_GrGLVendor == ctxInfo.vendor() || kImagination_GrGLVendor == ctxInfo.vendor()) {
+        fFullClearIsFree = true;
+    }
+
     if (kDesktop_GrGLBinding == binding) {
         fVertexArrayObjectSupport = version >= GR_GL_VER(3, 0) ||
                                     ctxInfo.hasExtension("GL_ARB_vertex_array_object");
@@ -648,4 +654,5 @@ void GrGLCaps::print() const {
     GrPrintf("Use non-VBO for dynamic data: %s\n",
              (fUseNonVBOVertexAndIndexDynamicData ? "YES" : "NO"));
     GrPrintf("Discard FrameBuffer support: %s\n", (fDiscardFBSupport ? "YES" : "NO"));
+    GrPrintf("Full screen clear is free: %s\n", (fFullClearIsFree ? "YES" : "NO"));
 }
diff --git a/src/gpu/gl/GrGLCaps.h b/src/gpu/gl/GrGLCaps.h
index 81391ecc6b..c126a76774 100644
--- a/src/gpu/gl/GrGLCaps.h
+++ b/src/gpu/gl/GrGLCaps.h
@@ -248,6 +248,8 @@ public:
     /// Is there support for discarding the frame buffer
     bool discardFBSupport() const { return fDiscardFBSupport; }
 
+    bool fullClearIsFree() const { return fFullClearIsFree; }
+
 private:
     /**
      * Maintains a bit per GrPixelConfig. It is used to avoid redundantly
@@ -329,6 +331,7 @@ private:
     bool fIsCoreProfile : 1;
     bool fFixedFunctionSupport : 1;
     bool fDiscardFBSupport : 1;
+    bool fFullClearIsFree : 1;
 
     typedef GrDrawTargetCaps INHERITED;
 };
diff --git a/src/gpu/gl/GrGpuGL.cpp b/src/gpu/gl/GrGpuGL.cpp
index adbfc35bef..92e496c3ee 100644
--- a/src/gpu/gl/GrGpuGL.cpp
+++ b/src/gpu/gl/GrGpuGL.cpp
@@ -1255,12 +1255,16 @@ void GrGpuGL::flushScissor() {
     }
 }
 
-void GrGpuGL::onClear(const SkIRect* rect, GrColor color) {
+void GrGpuGL::onClear(const SkIRect* rect, GrColor color, bool canIgnoreRect) {
     const GrDrawState& drawState = this->getDrawState();
     const GrRenderTarget* rt = drawState.getRenderTarget();
     // parent class should never let us get here with no RT
     SkASSERT(NULL != rt);
 
+    if (canIgnoreRect && this->glCaps().fullClearIsFree()) {
+        rect = NULL;
+    }
+
     SkIRect clippedRect;
     if (NULL != rect) {
         // flushScissor expects rect to be clipped to the target.
diff --git a/src/gpu/gl/GrGpuGL.h b/src/gpu/gl/GrGpuGL.h
index 677e48cb0f..7c97080e5f 100644
--- a/src/gpu/gl/GrGpuGL.h
+++ b/src/gpu/gl/GrGpuGL.h
@@ -135,7 +135,7 @@ private:
         GrStencilBuffer* sb,
         GrRenderTarget* rt) SK_OVERRIDE;
 
-    virtual void onClear(const SkIRect* rect, GrColor color) SK_OVERRIDE;
+    virtual void onClear(const SkIRect* rect, GrColor color, bool canIgnoreRect) SK_OVERRIDE;
 
     virtual void onForceRenderTargetFlush() SK_OVERRIDE;