Fixed all overloaded virtual methods on Windows.

Fixed all overloaded virtual methods on Windows.

This fixes the 'overloaded-virtual' Clang warning on Windows (currently
disabled; will be enabled in a follow-up CL).

- PpapiThread::PreCacheFont: Renamed to PreCacheFontForFlash to avoid
  conflict with PreCacheFont method in base class ChildThreadImpl. (This
  method is only called by another method called PreCacheFontForFlash so
  the new name is appropriate.)
- PrintingContextSytemDialogWin::InitializeSettings: Renamed to
  InitializeSettingsWithRanges to avoid conflict with InitializeSettings
  in base class PrintingContextWin. (These two methods are called on
  different code paths and the former is not meant to override the
  latter, so they should have different names.)
- Removed PrintingContextWin::ShowPrintDialog. This method was totally
  unused and its name was conflicting with a method in a subclass.

BUG=505301
Committed: https://crrev.com/8ca5918882daa6ab1be0c50825af47fe9a896b23
Cr-Commit-Position: refs/heads/master@{#337735}

[Matt Giuca, 2015-07-07 04:42:42]

mgiuca@chromium.org changed reviewers:
+ brettw@chromium.org, vitalybuka@chromium.org

[Matt Giuca, 2015-07-07 04:42:43]

vitalybuka@chromium.org: Please review changes in printing/*.

brettw@chromium.org: Please review changes in content/ppapi_plugin/* and
ppapi/*.

See CL description for rationale.

[Matt Giuca, 2015-07-07 04:43:01]

The CQ bit was checked by mgiuca@chromium.org to run a CQ dry run

[commit-bot: I haz the power, 2015-07-07 04:43:22]

Dry run: CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1216013005/40001

[commit-bot: I haz the power, 2015-07-07 05:29:47]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2015-07-07 05:29:48]

Dry run: This issue passed the CQ dry run.

[brettw, 2015-07-07 22:26:16]

lgtm

[Vitaly Buka (NO REVIEWS), 2015-07-07 22:33:14]

lgtm

[Matt Giuca, 2015-07-08 01:57:16]

The CQ bit was checked by mgiuca@chromium.org

[commit-bot: I haz the power, 2015-07-08 01:57:37]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1216013005/40001

[commit-bot: I haz the power, 2015-07-08 02:10:36]

Committed patchset #3 (id:40001)

[commit-bot: I haz the power, 2015-07-08 02:12:27]

Patchset 3 (id:??) landed as
https://crrev.com/8ca5918882daa6ab1be0c50825af47fe9a896b23
Cr-Commit-Position: refs/heads/master@{#337735}