Cleanup: Turn GrReducedClip into a class with a static function.

Clean up namespace usage.

Similar to what was done in
https://skia.googlesource.com/skia/+/a5414c4a8efc3119ee20fcee96c0bf68a04909c7

BUG=None
TEST=None
R=bsalomon@google.com

Review URL: https://codereview.chromium.org/653393003
diff --git a/src/gpu/GrReducedClip.h b/src/gpu/GrReducedClip.h
index e3a28cc..21899c7 100644
--- a/src/gpu/GrReducedClip.h
+++ b/src/gpu/GrReducedClip.h
@@ -1,4 +1,3 @@
-
 /*
  * Copyright 2012 Google Inc.
  *
@@ -12,37 +11,39 @@
 #include "SkClipStack.h"
 #include "SkTLList.h"
 
-namespace GrReducedClip {
+class SK_API GrReducedClip {
+public:
+    typedef SkTLList<SkClipStack::Element> ElementList;
 
-typedef SkTLList<SkClipStack::Element> ElementList;
+    enum InitialState {
+        kAllIn_InitialState,
+        kAllOut_InitialState,
+    };
 
-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. Optionally, the caller can request a tighter bounds on the
+     * clip be returned via tighterBounds. If not NULL, tighterBounds will
+     * always be contained by queryBounds after return. If tighterBounds is
+     * specified then it is assumed that the caller will implicitly clip against
+     * it. If the caller specifies non-NULL for requiresAA then it will indicate
+     * whether anti-aliasing is required to process any of the elements in the
+     * result.
+     *
+     * This may become a member function of SkClipStack when its interface is
+     * determined to be stable.
+     */
+    static void ReduceClipStack(const SkClipStack& stack,
+                                const SkIRect& queryBounds,
+                                ElementList* result,
+                                int32_t* resultGenID,
+                                InitialState* initialState,
+                                SkIRect* tighterBounds = NULL,
+                                bool* requiresAA = NULL);
 };
 
-/**
- * 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. Optionally, the caller can request a tighter bounds on the clip be returned via
- * tighterBounds. If not NULL, tighterBounds will always be contained by queryBounds after return.
- * If tighterBounds is specified then it is assumed that the caller will implicitly clip against it.
- * If the caller specifies non-NULL for requiresAA then it will indicate whether anti-aliasing is
- * required to process any of the elements in the result.
- *
- * This may become a member function of SkClipStack when its interface is determined to be stable.
- * Marked SK_API so that SkLua can call this in a shared library build.
- */
-SK_API void ReduceClipStack(const SkClipStack& stack,
-                            const SkIRect& queryBounds,
-                            ElementList* result,
-                            int32_t* resultGenID,
-                            InitialState* initialState,
-                            SkIRect* tighterBounds = NULL,
-                            bool* requiresAA = NULL);
-
-} // namespace GrReducedClip
-
 #endif