Reland of Mojo: Eliminate duplicate C API symbols

Reland of Mojo: Eliminate duplicate C API symbols (patchset #1 id:1 of https://codereview.chromium.org/2047813003/ )

Reason for revert:
Reverting this didn't fix the failure after all

Original issue's description:
> Revert of Mojo: Eliminate duplicate C API symbols (patchset #3 id:80001 of https://codereview.chromium.org/2044023004/ )
>
> Reason for revert:
> tentative revert due to linker errors. this doesn't make sense. nothing makes sense. RIP sanity
>
> Original issue's description:
> > Mojo: Eliminate duplicate C API symbols
> >
> > This gets rid of the duplicate definitions of public
> > Mojo C API symbols, instead making mojo/public/c/system
> > the singular source of these definitions. This allows
> > targets to be linked against mojo/public libraries
> > without requiring any additional EDK dependencies at
> > build time.
> >
> > To facilitate this the EDK uses the same set of API
> > thunks as the public library, and the public library
> > exposes a special embedder API (distinct from the DSO
> > MojoSetSystemThunks call used by the native app loader)
> > for setting these thunks. The MojoSetSystemThunks API
> > is moved to a module which is only linked directly into
> > app DSOs.
> >
> > Because mojo/public/c/system and mojo/edk/system are
> > now both components, and because there are no longer
> > redundant exports between the two, it's now safe for
> > targets to depend on either one or both of them as
> > needed without encountering duplicate definitions.
> >
> > Also some opportunistic cleanup of Mojo build rules.
> >
> > BUG=612500
> >
> > Committed: https://crrev.com/464e306a82ead839f02f1930a684400228b72495
> > Cr-Commit-Position: refs/heads/master@{#398605}
>
> TBR=jam@chromium.org
> # Skipping CQ checks because original CL landed less than 1 days ago.
> NOPRESUBMIT=true
> NOTREECHECKS=true
> NOTRY=true
> BUG=612500
>
> Committed: https://crrev.com/e8e242161954d86ce8e064f8a6515bc818d5b600
> Cr-Commit-Position: refs/heads/master@{#398614}

TBR=jam@chromium.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=612500
Committed: https://crrev.com/26ec28cabbdcc430483d5f4996b3afaafb1ba1bf
Cr-Commit-Position: refs/heads/master@{#398622}

[Ken Rockot(use gerrit already), 2016-06-08 18:20:22]

The CQ bit was checked by rockot@chromium.org

[Ken Rockot(use gerrit already), 2016-06-08 18:20:22]

Created Reland of Mojo: Eliminate duplicate C API symbols

[commit-bot: I haz the power, 2016-06-08 18:20:58]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/2048053003/1

[commit-bot: I haz the power, 2016-06-08 18:22:31]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2016-06-08 18:23:26]

Description was changed from

==========
Reland of Mojo: Eliminate duplicate C API symbols (patchset #1 id:1 of
https://codereview.chromium.org/2047813003/ )

Reason for revert:
Reverting this didn't fix the failure after all

Original issue's description:
> Revert of Mojo: Eliminate duplicate C API symbols (patchset #3 id:80001 of
https://codereview.chromium.org/2044023004/ )
> 
> Reason for revert:
> tentative revert due to linker errors. this doesn't make sense. nothing makes
sense. RIP sanity
> 
> Original issue's description:
> > Mojo: Eliminate duplicate C API symbols
> >
> > This gets rid of the duplicate definitions of public
> > Mojo C API symbols, instead making mojo/public/c/system
> > the singular source of these definitions. This allows
> > targets to be linked against mojo/public libraries
> > without requiring any additional EDK dependencies at
> > build time.
> >
> > To facilitate this the EDK uses the same set of API
> > thunks as the public library, and the public library
> > exposes a special embedder API (distinct from the DSO
> > MojoSetSystemThunks call used by the native app loader)
> > for setting these thunks. The MojoSetSystemThunks API
> > is moved to a module which is only linked directly into
> > app DSOs.
> >
> > Because mojo/public/c/system and mojo/edk/system are
> > now both components, and because there are no longer
> > redundant exports between the two, it's now safe for
> > targets to depend on either one or both of them as
> > needed without encountering duplicate definitions.
> >
> > Also some opportunistic cleanup of Mojo build rules.
> >
> > BUG=612500
> >
> > Committed: https://crrev.com/464e306a82ead839f02f1930a684400228b72495
> > Cr-Commit-Position: refs/heads/master@{#398605}
> 
> TBR=jam@chromium.org
> # Skipping CQ checks because original CL landed less than 1 days ago.
> NOPRESUBMIT=true
> NOTREECHECKS=true
> NOTRY=true
> BUG=612500
> 
> Committed: https://crrev.com/e8e242161954d86ce8e064f8a6515bc818d5b600
> Cr-Commit-Position: refs/heads/master@{#398614}

TBR=jam@chromium.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=612500
==========

to

==========
Reland of Mojo: Eliminate duplicate C API symbols (patchset #1 id:1 of
https://codereview.chromium.org/2047813003/ )

Reason for revert:
Reverting this didn't fix the failure after all

Original issue's description:
> Revert of Mojo: Eliminate duplicate C API symbols (patchset #3 id:80001 of
https://codereview.chromium.org/2044023004/ )
>
> Reason for revert:
> tentative revert due to linker errors. this doesn't make sense. nothing makes
sense. RIP sanity
>
> Original issue's description:
> > Mojo: Eliminate duplicate C API symbols
> >
> > This gets rid of the duplicate definitions of public
> > Mojo C API symbols, instead making mojo/public/c/system
> > the singular source of these definitions. This allows
> > targets to be linked against mojo/public libraries
> > without requiring any additional EDK dependencies at
> > build time.
> >
> > To facilitate this the EDK uses the same set of API
> > thunks as the public library, and the public library
> > exposes a special embedder API (distinct from the DSO
> > MojoSetSystemThunks call used by the native app loader)
> > for setting these thunks. The MojoSetSystemThunks API
> > is moved to a module which is only linked directly into
> > app DSOs.
> >
> > Because mojo/public/c/system and mojo/edk/system are
> > now both components, and because there are no longer
> > redundant exports between the two, it's now safe for
> > targets to depend on either one or both of them as
> > needed without encountering duplicate definitions.
> >
> > Also some opportunistic cleanup of Mojo build rules.
> >
> > BUG=612500
> >
> > Committed: https://crrev.com/464e306a82ead839f02f1930a684400228b72495
> > Cr-Commit-Position: refs/heads/master@{#398605}
>
> TBR=jam@chromium.org
> # Skipping CQ checks because original CL landed less than 1 days ago.
> NOPRESUBMIT=true
> NOTREECHECKS=true
> NOTRY=true
> BUG=612500
>
> Committed: https://crrev.com/e8e242161954d86ce8e064f8a6515bc818d5b600
> Cr-Commit-Position: refs/heads/master@{#398614}

TBR=jam@chromium.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=612500

Committed: https://crrev.com/26ec28cabbdcc430483d5f4996b3afaafb1ba1bf
Cr-Commit-Position: refs/heads/master@{#398622}
==========

[commit-bot: I haz the power, 2016-06-08 18:23:27]

Patchset 1 (id:??) landed as
https://crrev.com/26ec28cabbdcc430483d5f4996b3afaafb1ba1bf
Cr-Commit-Position: refs/heads/master@{#398622}

[Ken Rockot(use gerrit already), 2016-06-08 19:50:08]

A revert of this CL (patchset #1 id:1) has been created in
https://codereview.chromium.org/2054513002/ by rockot@chromium.org.

The reason for reverting is: trying to revert again, and then clobber. seemed to
have fixed the error locally.