Set maximum output size for scaled-image-cache images

tests/ScaledImageCache.cpp

+/*
+ * Copyright 2014 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+#include "Test.h"
+#include "SkGraphics.h"
+#include "SkCanvas.h"
+
+static const int kCanvasSize = 1;
+static const int kBitmapSize = 16;
+static const int kScale = 8;
+
+static size_t test_scaled_image_cache_useage() {
+    SkAutoTUnref<SkCanvas> canvas(
+            SkCanvas::NewRasterN32(kCanvasSize, kCanvasSize));
+    SkBitmap bitmap;
+    SkAssertResult(bitmap.allocN32Pixels(kBitmapSize, kBitmapSize));
+    SkScalar scaledSize = SkIntToScalar(kScale * kBitmapSize);
+    canvas->clipRect(SkRect::MakeLTRB(0, 0, scaledSize, scaledSize));
+    SkPaint paint;
+    paint.setFilterLevel(SkPaint::kHigh_FilterLevel);
+    size_t bytesUsed = SkGraphics::GetImageCacheBytesUsed();
+    canvas->drawBitmapRect(bitmap,
+                           SkRect::MakeLTRB(0, 0, scaledSize, scaledSize),
+                           &paint);
+    return SkGraphics::GetImageCacheBytesUsed() - bytesUsed;
+}
+
+// http://crbug.com/389439
+DEF_TEST(ScaledImageCache_SingleAllocationByteLimit, reporter) {
+    size_t originalByteLimit = SkGraphics::GetImageCacheByteLimit();
+    size_t originalAllocationLimit =
+        SkGraphics::GetImageCacheSingleAllocationByteLimit();
+
+    size_t size = kBitmapSize * kScale * kBitmapSize * kScale
+        * SkColorTypeBytesPerPixel(kN32_SkColorType);
+
+    SkGraphics::SetImageCacheByteLimit(0); // clear cache
+    SkGraphics::SetImageCacheByteLimit(2 * size);
+    SkGraphics::SetImageCacheSingleAllocationByteLimit(0);
+
+    REPORTER_ASSERT(reporter, size == test_scaled_image_cache_useage());
+
+    SkGraphics::SetImageCacheByteLimit(0); // clear cache
+    SkGraphics::SetImageCacheByteLimit(2 * size);
+    SkGraphics::SetImageCacheSingleAllocationByteLimit(size * 2);
+
+    REPORTER_ASSERT(reporter, size == test_scaled_image_cache_useage());
+
+    SkGraphics::SetImageCacheByteLimit(0); // clear cache
+    SkGraphics::SetImageCacheByteLimit(2 * size);
+    SkGraphics::SetImageCacheSingleAllocationByteLimit(size / 2);
+
+    REPORTER_ASSERT(reporter, 0 == test_scaled_image_cache_useage());
+
+    SkGraphics::SetImageCacheSingleAllocationByteLimit(originalAllocationLimit);
+    SkGraphics::SetImageCacheByteLimit(originalByteLimit);
+}