Signal chrome_elf to initialize crash reporting, rather than doing it in DllMain

Currently, initialization crash reporting indirectly calls
CreateProcess() from chrome_elf's DllMain(), which causes deadlock in
some configurations (showing up in M54).

Instead, signal to chrome_elf that it should initialize crash reporting
later in WinMain(). This means we lose a little coverage that we were
hoping to gain from the move to chrome_elf, but a localized fix is
required for merge to stable.

Follow up bug is

BUG=655788, 656800
TEST=enforce certificate rules per and then try to launch chrome.

Cr-Commit-Position: refs/heads/master@{#425840}
(cherry picked from commit f3a5670dd8d42b045d31625dde4a2561b471138f)

Review URL: .

Cr-Commit-Position: refs/branch-heads/2840@{#754}
Cr-Branched-From: 1ae106dbab4bddd85132d5b75c670794311f4c57-refs/heads/master@{#414607}
4 files changed