Adding option to SkTileGrid for specifying border pixels.

The purpose of this patch is to make it possible for the chromium compositor to
generate a TileGrid structure that is better suited for scaled playback.
Review URL: https://codereview.appspot.com/7300072

git-svn-id: http://skia.googlecode.com/svn/trunk@7680 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/tests/TileGridTest.cpp b/tests/TileGridTest.cpp
index 1946b9f..afde41d 100644
--- a/tests/TileGridTest.cpp
+++ b/tests/TileGridTest.cpp
@@ -39,8 +39,9 @@
 
 class TileGridTest {
 public:
-    static void verifyTileHits(skiatest::Reporter* reporter, SkIRect rect, uint32_t tileMask) {
-        SkTileGrid grid(10, 10, 2, 2, NULL);
+    static void verifyTileHits(skiatest::Reporter* reporter, SkIRect rect, uint32_t tileMask, 
+                               int borderPixels = 0) {
+        SkTileGrid grid(10, 10, 2, 2, borderPixels, NULL);
         grid.insert(NULL, rect, false);
         REPORTER_ASSERT(reporter, grid.tile(0,0).count() ==
             ((tileMask & kTopLeft_Tile)? 1 : 0));
@@ -119,6 +120,12 @@
         verifyTileHits(reporter, SkIRect::MakeXYWH(10, 10, 1, 1),  kAll_Tile);
         verifyTileHits(reporter, SkIRect::MakeXYWH(11, 11, 1, 1),  kBottomRight_Tile);
 
+        // BorderPixels
+        verifyTileHits(reporter, SkIRect::MakeXYWH(0, 0, 7, 7),  kTopLeft_Tile, 1);
+        verifyTileHits(reporter, SkIRect::MakeXYWH(0, 0, 8, 8),  kAll_Tile, 1);
+        verifyTileHits(reporter, SkIRect::MakeXYWH(11, 11, 1, 1),  kAll_Tile, 1);
+        verifyTileHits(reporter, SkIRect::MakeXYWH(12, 12, 1, 1),  kBottomRight_Tile, 1);
+
         // BBoxes that overlap tiles
         verifyTileHits(reporter, SkIRect::MakeXYWH(5, 5, 10, 1),  kTopLeft_Tile | kTopRight_Tile);
         verifyTileHits(reporter, SkIRect::MakeXYWH(5, 5, 1, 10),  kTopLeft_Tile |