Allow GrReducedClip to take non-integer query bounds

src/gpu/GrReducedClip.h

 /*
  * Copyright 2012 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #ifndef GrReducedClip_DEFINED
 #define GrReducedClip_DEFINED
 
 #include "SkClipStack.h"
 #include "SkTLList.h"
 
 class SK_API GrReducedClip {
 public:
     typedef SkTLList<SkClipStack::Element, 16> ElementList;
 
     enum InitialState {
         kAllIn_InitialState,
         kAllOut_InitialState,
     };
 
     /**
-     * This function takes a clip stack and a query rectangle and it produces a
-     * reduced set of SkClipStack::Elements that are equivalent to applying the
-     * full stack to the rectangle. The clip stack generation id that represents
-     * the list of elements is returned in resultGenID. The initial state of the
-     * query rectangle before the first clip element is applied is returned via
-     * initialState. The reducer output tighterBounds is a tighter bounds on the
-     * clip. tighterBounds will always be contained by queryBounds after return.
-     * It is assumed that the caller will not draw outside of tighterBounds.
-     * The requiresAA output will indicate whether anti-aliasing is required to
-     * process any of the elements in the element list result.
+     * This function produces a reduced set of SkClipStack::Elements that are equivalent to applying
+     * a full clip stack within a specified query rectangle.
+     *
+     * @param stack          the clip stack to reduce.
+     * @param queryBounds    bounding box of geometry the stack will clip.
+     * @param result         populated with a minimal list of elements that implement the clip
+     *                       within the provided query bounds.
+     * @param resultGenID    uniquely identifies the resulting reduced clip.
+     * @param clipIBounds    bounding box within which the reduced clip is valid. The caller must
+     *                       not draw any pixels outside this box. NOTE: this box may be undefined
+     *                       if no pixels are valid (e.g. empty result, "all out" initial state.)
+     * @param requiresAA     indicates whether anti-aliasing is required to process any of the
+     *                       elements in the element list result. Undefined if the result is empty.
+     * @return the initial clip state within clipIBounds ("all in" or "all out").
      */
-    static void ReduceClipStack(const SkClipStack& stack,
-                                const SkIRect& queryBounds,
-                                ElementList* result,
-                                int32_t* resultGenID,
-                                InitialState* initialState,
-                                SkIRect* tighterBounds,
-                                bool* requiresAA);
+    static InitialState ReduceClipStack(const SkClipStack& stack,
+                                        const SkRect& queryBounds,
+                                        ElementList* result,
+                                        int32_t* resultGenID,
+                                        SkIRect* clipIBounds,
+                                        bool* requiresAA);
 };
 
 #endif