History: Add UMA collection for full history sync.

History: Add UMA collection for full history sync.

In order to keep track of how many visits from the local DB also
appeared on the server, this CL changes the way local entries are
combined with entries from the server. Rather than mixing the results
in a single list when they arrive, they are kept separate until just
before they are returned to the front end. This also fixes a bug
where the merged view would not be correct if less than |max_count|
unique results were received from the history server.

BUG=177073
Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=186440

[Patrick Dubroy, 2013-03-04 18:20:20]

James, please take a look.

[James Hawkins, 2013-03-04 19:09:45]

LGTM with nits.

https://codereview.chromium.org/12381081/diff/1/chrome/browser/ui/webui/histo...
File chrome/browser/ui/webui/history_ui.h (right):

https://codereview.chromium.org/12381081/diff/1/chrome/browser/ui/webui/histo...
chrome/browser/ui/webui/history_ui.h:42: base::Time time, const std::set<int64>&
timestamps,
nit: The start of parameter rows must align on the same column (i.e., push
forward this row or drop down the first row).

https://codereview.chromium.org/12381081/diff/1/chrome/browser/ui/webui/histo...
chrome/browser/ui/webui/history_ui.h:59: EntryType entry_type;
Optional nit: The type name itself is not quite descriptive enough to allow the
casual reader to understand this member variable; I'd document it here.

[Patrick Dubroy, 2013-03-05 13:15:54]

https://codereview.chromium.org/12381081/diff/1/chrome/browser/ui/webui/histo...
File chrome/browser/ui/webui/history_ui.h (right):

https://codereview.chromium.org/12381081/diff/1/chrome/browser/ui/webui/histo...
chrome/browser/ui/webui/history_ui.h:42: base::Time time, const std::set<int64>&
timestamps,
On 2013/03/04 19:09:45, James Hawkins wrote:
> nit: The start of parameter rows must align on the same column (i.e., push
> forward this row or drop down the first row).

Fixed. So google-style.el *was* doing the right thing :-)

https://codereview.chromium.org/12381081/diff/1/chrome/browser/ui/webui/histo...
chrome/browser/ui/webui/history_ui.h:59: EntryType entry_type;
On 2013/03/04 19:09:45, James Hawkins wrote:
> Optional nit: The type name itself is not quite descriptive enough to allow
the
> casual reader to understand this member variable; I'd document it here.

Done.

[Patrick Dubroy, 2013-03-06 15:21:27]

Committed patchset #3 manually as r186440 (presubmit successful).