Refactor of Histogram related code

base/metrics/bucket_ranges.cc

Index: base/metrics/bucket_ranges.cc
===================================================================
--- base/metrics/bucket_ranges.cc	(revision 148055)
+++ base/metrics/bucket_ranges.cc	(working copy)
@@ -11,7 +11,7 @@
 namespace base {
 
 // Static table of checksums for all possible 8 bit bytes.
-static const uint32 kCrcTable[256] = { 0x0, 0x77073096L, 0xee0e612cL,
+const uint32 kCrcTable[256] = { 0x0, 0x77073096L, 0xee0e612cL,
 0x990951baL, 0x76dc419L, 0x706af48fL, 0xe963a535L, 0x9e6495a3L, 0xedb8832L,
 0x79dcb8a4L, 0xe0d5e91eL, 0x97d2d988L, 0x9b64c2bL, 0x7eb17cbdL, 0xe7b82d07L,
 0x90bf1d91L, 0x1db71064L, 0x6ab020f2L, 0xf3b97148L, 0x84be41deL, 0x1adad47dL,
@@ -107,7 +107,7 @@
   ranges_[i] = value;
 }
 
-uint32 BucketRanges::CalculateChecksum() {
+uint32 BucketRanges::CalculateChecksum() const {
   // Seed checksum.
   uint32 checksum = static_cast<uint32>(ranges_.size());
 
@@ -116,7 +116,7 @@
   return checksum;
 }
 
-bool BucketRanges::HasValidChecksum() {
+bool BucketRanges::HasValidChecksum() const {
   return CalculateChecksum() == checksum_;
 }