[sqlite] Respect the gyp and gn component switch.

[sqlite] Respect the gyp and gn component switch.

SQLITE_API is the existing mechanism SQLite provides, and is used in
preference to inventing a new SQLITE_EXPORT symbol (like
sql/sql_export.h and other examples).

CoreServices.framework is necessary on OSX because of the Time Machine
patch.

Remove sql/proxy.{h,cc}, which was necessary to work around SQLite
linking statically into both component shlibs and unit test executables.

[Relanding https://codereview.chromium.org/1322463002/ ]

BUG=489444
TBR=michaeln@chromium.org, thakis@chromium.org

Committed: https://crrev.com/02ce712af589a5b722ebbf5c2fffb3e0d4849963
Cr-Commit-Position: refs/heads/master@{#346212}

[Scott Hess - ex-Googler, 2015-08-28 18:12:51]

Fix dumb BUILD.gn osx/win breakage.

[Scott Hess - ex-Googler, 2015-08-28 18:17:23]

shess@chromium.org changed reviewers:
+ michaeln@chromium.org, thakis@chromium.org

[Scott Hess - ex-Googler, 2015-08-28 18:17:23]

Relanding https://codereview.chromium.org/1322463002/ (which Michael lgtm'ed)
with patch 1 from  https://codereview.chromium.org/1313013008/ (which Nico
lgtm'ed).  I'll probably just TBR, though I'm also going to let it hang out for
a bit to make sure the original revert sticks.

[Scott Hess - ex-Googler, 2015-08-28 19:15:01]

The CQ bit was checked by shess@chromium.org

[commit-bot: I haz the power, 2015-08-28 19:15:20]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1325513002/20001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1325513002/20001

[commit-bot: I haz the power, 2015-08-28 19:39:29]

Committed patchset #2 (id:20001)

[commit-bot: I haz the power, 2015-08-28 19:40:15]

Patchset 2 (id:??) landed as
https://crrev.com/02ce712af589a5b722ebbf5c2fffb3e0d4849963
Cr-Commit-Position: refs/heads/master@{#346212}

[Scott Hess - ex-Googler, 2015-08-28 19:52:59]

A revert of this CL (patchset #2 id:20001) has been created in
https://codereview.chromium.org/1307363007/ by shess@chromium.org.

The reason for reverting is: ARRGH!  win8_chromium_gn_dgb is still broken..