cc: Fix a bug where filter outsets for drop-shadow could be negative.

cc/output/filter_operations_unittest.cc

 // Copyright 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include <stddef.h>
 
 #include "cc/output/filter_operations.h"
 #include "testing/gtest/include/gtest/gtest.h"
 #include "third_party/skia/include/effects/SkBlurImageFilter.h"
 #include "third_party/skia/include/effects/SkDropShadowImageFilter.h"
@@ skipping 166 matching lines @@
             ops.MapRect(gfx::Rect(0, 0, 10, 10), SkMatrix::I()));
 }
 
 TEST(FilterOperationsTest, MapRectReverseDropShadow) {
   FilterOperations ops;
   ops.Append(FilterOperation::CreateDropShadowFilter(gfx::Point(3, 8), 20, 0));
   EXPECT_EQ(gfx::Rect(-63, -68, 130, 130),
             ops.MapRectReverse(gfx::Rect(0, 0, 10, 10), SkMatrix::I()));
 }
 
+TEST(FilterOperationsTest, GetOutsetsDropShadowDoesNotContract) {
+  // Even with a drop-shadow, the original content is still drawn. Thus the
+  // content bounds are never contracted due to a drop-shadow.
+  FilterOperations ops;
+  ops.Append(FilterOperation::CreateDropShadowFilter(gfx::Point(3, 8), 0, 0));
+  int top, right, bottom, left;
+  top = right = bottom = left = 0;
+  ops.GetOutsets(&top, &right, &bottom, &left);
+  EXPECT_EQ(0, top);
+  EXPECT_EQ(3, right);
+  EXPECT_EQ(8, bottom);
+  EXPECT_EQ(0, left);
+}
+
+TEST(FilterOperationsTest, MapRectDropShadowDoesNotContract) {
+  // Even with a drop-shadow, the original content is still drawn. Thus the
+  // content bounds are never contracted due to a drop-shadow.
+  FilterOperations ops;
+  ops.Append(FilterOperation::CreateDropShadowFilter(gfx::Point(3, 8), 0, 0));
+  EXPECT_EQ(gfx::Rect(0, 0, 13, 18),
+            ops.MapRect(gfx::Rect(0, 0, 10, 10), SkMatrix::I()));
+}
+
+TEST(FilterOperationsTest, MapRectReverseDropShadowDoesNotContract) {
+  // Even with a drop-shadow, the original content is still drawn. Thus the
+  // content bounds are never contracted due to a drop-shadow.
+  FilterOperations ops;
+  ops.Append(FilterOperation::CreateDropShadowFilter(gfx::Point(3, 8), 0, 0));
+  EXPECT_EQ(gfx::Rect(-3, -8, 13, 18),
+            ops.MapRectReverse(gfx::Rect(0, 0, 10, 10), SkMatrix::I()));
+}
+
 #define SAVE_RESTORE_AMOUNT(filter_name, filter_type, a)                  \
   {                                                                       \
     FilterOperation op = FilterOperation::Create##filter_name##Filter(a); \
     EXPECT_EQ(FilterOperation::filter_type, op.type());                   \
     EXPECT_EQ(a, op.amount());                                            \
                                                                           \
     FilterOperation op2 = FilterOperation::CreateEmptyFilter();           \
     op2.set_type(FilterOperation::filter_type);                           \
                                                                           \
     EXPECT_NE(a, op2.amount());                                           \
@@ skipping 645 matching lines @@
   blended = to.Blend(from, -0.75);
   EXPECT_EQ(to, blended);
   blended = to.Blend(from, 0.75);
   EXPECT_EQ(to, blended);
   blended = to.Blend(from, 1.5);
   EXPECT_EQ(to, blended);
 }
 
 }  // namespace
 }  // namespace cc