Make BBH::search() const.

src/core/SkTileGrid.cpp

Index: src/core/SkTileGrid.cpp
diff --git a/src/core/SkTileGrid.cpp b/src/core/SkTileGrid.cpp
index 35f85d26c9647cbc5b5058dd9fb948ed0d5fabdb..98fc7f9d62720c9561d2206818994e6a2a61f013 100644
--- a/src/core/SkTileGrid.cpp
+++ b/src/core/SkTileGrid.cpp
@@ -33,7 +33,7 @@ int SkTileGrid::tileCount(int x, int y) {
     return this->tile(x, y).count();
 }
 
-SkTDArray<void *>& SkTileGrid::tile(int x, int y) {
+SkTDArray<void *>& SkTileGrid::tile(int x, int y) const {
     return fTileData[y * fXTileCount + x];
 }
 
@@ -65,7 +65,7 @@ void SkTileGrid::insert(void* data, const SkIRect& bounds, bool) {
     fInsertionCount++;
 }
 
-void SkTileGrid::search(const SkIRect& query, SkTDArray<void*>* results) {
+void SkTileGrid::search(const SkIRect& query, SkTDArray<void*>* results) const {
     SkIRect adjustedQuery = query;
     // The inset is to counteract the outset that was applied in 'insert'
     // The outset/inset is to optimize for lookups of size