initial preroll api

BUG=skia:

Review URL: https://codereview.chromium.org/855473002

4 files changed, 22 insertions, 1 deletions

diff --git a/include/core/SkCanvas.h b/include/core/SkCanvas.h
index 4e7ed3066e..3eecaf760a 100644
--- a/include/core/SkCanvas.h
+++ b/include/core/SkCanvas.h
@@ -87,7 +87,7 @@ public:
      *  by any device/pixels. Typically this use used by subclasses who handle
      *  the draw calls in some other way.
      */
-    SkCanvas(int width, int height);
+    SkCanvas(int width, int height, const SkSurfaceProps* = NULL);
 
     /** Construct a canvas with the specified device to draw into.
 
diff --git a/include/core/SkImage.h b/include/core/SkImage.h
index b0587b2c3a..f59042cada 100644
--- a/include/core/SkImage.h
+++ b/include/core/SkImage.h
@@ -131,6 +131,8 @@ public:
      */
     SkSurface* newSurface(const SkImageInfo&, const SkSurfaceProps* = NULL) const;
 
+    void preroll() const;
+
     const char* toString(SkString*) const;
 
     /**
diff --git a/include/core/SkPicture.h b/include/core/SkPicture.h
index 5b2f7a99f7..5a48476db0 100644
--- a/include/core/SkPicture.h
+++ b/include/core/SkPicture.h
@@ -171,6 +171,22 @@ public:
      */
     bool willPlayBackBitmaps() const;
 
+    /**
+     *  This is a general hint that the picture will (soon) be drawn into a SkCanvas with
+     *  corresponding attributes (e.g. clip, matrix, props). No drawing occurs, but some
+     *  expensive operations may be run (e.g. image decoding).
+     *
+     *  Any of the parameters may be NULL.
+     *
+     *  @param srcBounds If not NULL, this is the subset of the picture (in the same coordinates
+     *                   as the picture's bounds) that preroll() should focus on.
+     *  @param initialMatrix If not NULL, this is the initialMatrix that is expected when the
+     *                       picture is actually drawn.
+     *  @param props If not NULL, these are the expected props when the picture is actually drawn.
+     */
+    void preroll(const SkRect* srcBounds, const SkMatrix* initialMatrix, const SkSurfaceProps*,
+                 void* gpuCacheAccessor) const;
+
     /** Return true if the SkStream/Buffer represents a serialized picture, and
         fills out SkPictInfo. After this function returns, the data source is not
         rewound so it will have to be manually reset before passing to
diff --git a/include/core/SkShader.h b/include/core/SkShader.h
index f8de276c7b..1ae531e2e5 100644
--- a/include/core/SkShader.h
+++ b/include/core/SkShader.h
@@ -478,6 +478,8 @@ public:
      */
     virtual SkShader* refAsALocalMatrixShader(SkMatrix* localMatrix) const;
 
+    void preroll() const { this->onPreroll(); }
+
     SK_TO_STRING_VIRT()
     SK_DEFINE_FLATTENABLE_TYPE(SkShader)
 
@@ -492,6 +494,7 @@ protected:
      */
     virtual Context* onCreateContext(const ContextRec&, void* storage) const;
 
+    virtual void onPreroll() const {}
     virtual bool onAsLuminanceColor(SkColor*) const {
         return false;
     }