Reduce window rectangles cap to 8

src/gpu/gl/GrGLGpu.cpp

 /*
  * Copyright 2011 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "GrGLGpu.h"
 #include "GrGLBuffer.h"
 #include "GrGLGLSL.h"
@@ skipping 1986 matching lines @@
 }
 
 void GrGLGpu::flushWindowRectangles(const GrWindowRectangles& windows, const GrGLRenderTarget* rt) {
     typedef GrWindowRectangles::Mode Mode;
     SkASSERT(windows.count() <= this->caps()->maxWindowRectangles());
     SkASSERT(windows.disabled() || rt->renderFBOID()); // Window rectangles can't be used on-screen.
 
     if (!this->caps()->maxWindowRectangles() ||
         fHWWindowRects.equal(rt->origin(), rt->getViewport(), windows)) {
         return;
+    }
 
-    }
+    // This is purely a workaround for a spurious warning generated by gcc. Otherwise the above
+    // assert would be sufficient. https://gcc.gnu.org/bugzilla/show_bug.cgi?id=5912
+    int numWindows = SkTMin(windows.count(), int(GrWindowRectangles::kMaxWindows));
+    SkASSERT(windows.count() == numWindows);
 
     GrGLIRect glwindows[GrWindowRectangles::kMaxWindows];
     const SkIRect* skwindows = windows.data();
-    for (int i = 0; i < windows.count(); ++i) {
+    for (int i = 0; i < numWindows; ++i) {
         glwindows[i].setRelativeTo(rt->getViewport(), skwindows[i], rt->origin());
     }
 
     GrGLenum glmode = (Mode::kExclusive == windows.mode()) ? GR_GL_EXCLUSIVE : GR_GL_INCLUSIVE;
-    GL_CALL(WindowRectangles(glmode, windows.count(), glwindows->asInts()));
+    GL_CALL(WindowRectangles(glmode, numWindows, glwindows->asInts()));
 
     fHWWindowRects.set(rt->origin(), rt->getViewport(), windows);
 }
 
 void GrGLGpu::disableWindowRectangles() {
     if (!this->caps()->maxWindowRectangles() || fHWWindowRects.disabled()) {
         return;
     }
     GL_CALL(WindowRectangles(GR_GL_EXCLUSIVE, 0, nullptr));
     fHWWindowRects.setDisabled();
@@ skipping 2629 matching lines @@
         if (GR_GL_TEXTURE_EXTERNAL == glTexture->target() ||
             GR_GL_TEXTURE_RECTANGLE == glTexture->target()) {
             copyParams->fFilter = GrTextureParams::kNone_FilterMode;
             copyParams->fWidth = texture->width();
             copyParams->fHeight = texture->height();
             return true;
         }
     }
     return false;
 }