Disk cache: Introduce BlockBitmaps for V3.

net/disk_cache/block_files.h

Index: net/disk_cache/block_files.h
===================================================================
--- net/disk_cache/block_files.h	(revision 210990)
+++ net/disk_cache/block_files.h	(working copy)
@@ -49,8 +49,12 @@
 
   // Returns true if the current block file should not be used as-is to store
   // more records. |block_count| is the number of blocks to allocate.
-  bool NeedToGrowBlockFile(int block_count);
+  bool NeedToGrowBlockFile(int block_count) const;
 
+  // Returns true if this block file can be used to store an extra record of
+  // size |block_count|.
+  bool CanAllocate(int block_count) const;
+
   // Returns the number of empty blocks for this file.
   int EmptyBlocks() const;
 
@@ -60,9 +64,8 @@
   // Returns the size of the wrapped structure (BlockFileHeader).
   int Size() const;
 
-  BlockFileHeader* operator->() { return header_; }
-  void operator=(const BlockHeader& other) { header_ = other.header_; }
-  BlockFileHeader* Get() { return header_; }
+  // Returns a pointer to the underlying BlockFileHeader.

[gavinp, 2013/08/05 17:06:15]

Is it appropriate to add a TODO(rvargas): Remove this accessor after v3 cache
finishes landing?

[gavinp, 2013/08/26 14:30:56]

Do these TODO comments make sense? I was asking as much to make sure I
understand what's happening as to improve the code?

+  BlockFileHeader* Header();
 
  private:
   BlockFileHeader* header_;