Reduce window rectangles cap to 8

src/gpu/GrWindowRectangles.h

 /*
  * Copyright 2016 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #ifndef GrWindowRectangles_DEFINED
 #define GrWindowRectangles_DEFINED
 
 #include "GrNonAtomicRef.h"
 #include "SkRect.h"
 
 class GrWindowRectangles {
 public:
-    constexpr static int kMaxWindows = 16;
+    constexpr static int kMaxWindows = 8;
 
     enum class Mode : bool {
         kExclusive,
         kInclusive
     };
 
     GrWindowRectangles(Mode mode = Mode::kExclusive) : fMode(mode), fCount(0) {}
     GrWindowRectangles(const GrWindowRectangles& that) : fCount(0) { *this = that; }
     ~GrWindowRectangles() { SkSafeUnref(this->rec()); }
 
     Mode mode() const { return fMode; }
-    uint16_t count() const { return fCount; }
+    int count() const { return fCount; }
     bool disabled() const { return Mode::kExclusive == fMode && !fCount; }
     const SkIRect* data() const;
 
     void reset(Mode = Mode::kExclusive);
     GrWindowRectangles& operator=(const GrWindowRectangles&);
 
     SkIRect& addWindow(const SkIRect& window) { return this->addWindow() = window; }
     SkIRect& addWindow();
 
     bool operator!=(const GrWindowRectangles& that) const { return !(*this == that); }
@@ skipping 62 matching lines @@
     if (fMode != that.fMode || fCount != that.fCount) {
         return false;
     }
     if (fCount > kNumLocalWindows && fRec == that.fRec) {
         return true;
     }
     return !fCount || !memcmp(this->data(), that.data(), sizeof(SkIRect) * fCount);
 }
 
 #endif