Improving comment in SkTileGrid::search

TBR=reed

git-svn-id: http://skia.googlecode.com/svn/trunk@6828 2bbb7eff-a529-9590-31e7-b0007b416f81

src/core/SkTileGrid.cpp

@@ -73,8 +73,10 @@ void SkTileGrid::search(const SkIRect& query, SkTDArray<void*>* results) {
         results->reset();
         SkTDArray<int> curPositions;
         curPositions.setCount(queryTileCount);
-        // Note: Reserving space for 1024 tile pointers on the stack. If the malloc
-        // becomes a bottleneck, we may consider increasing that number.
+        // Note: Reserving space for 1024 tile pointers on the stack. If the
+        // malloc becomes a bottleneck, we may consider increasing that number.
+        // Typical large web page, say 2k x 16k, would require 512 tiles of
+        // size 256 x 256 pixels.
         SkAutoSTArray<1024, SkTDArray<void *>*> storage(queryTileCount);
         SkTDArray<void *>** tileRange = storage.get();
         int tile = 0;