Revert "Disable renderer CIG by default."

This reverts commit 6bbf3348.

Reason for revert: The issue is now fixed. Relanding.

Original change's description:
> Disable renderer CIG by default.
> 
> This is causing crashes on some configurations and needs investigation.
> 
> BUG=750886,990640
> 
> Change-Id: Idfdd06b219a95bed854cce9048860692ded011b3
> Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1736106
> Commit-Queue: Will Harris <wfh@chromium.org>
> Commit-Queue: James Forshaw <forshaw@chromium.org>
> Reviewed-by: James Forshaw <forshaw@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#683904}

TBR=forshaw@chromium.org,wfh@chromium.org

Change-Id: I84f75f23b897770fd5429a400086db78aff52479
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: 750886, 990640
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1737434Reviewed-by: Will Harris <wfh@chromium.org>
Commit-Queue: Will Harris <wfh@chromium.org>
Cr-Commit-Position: refs/heads/master@{#684108}

chrome/browser/chrome_content_browser_client.cc

@@ -725,7 +725,7 @@ const char* const kPredefinedAllowedSocketOrigins[] = {
 // running on Windows 10 1511 and above. See
 // https://blogs.windows.com/blog/tag/code-integrity-guard/.
 const base::Feature kRendererCodeIntegrity{"RendererCodeIntegrity",
-                                           base::FEATURE_DISABLED_BY_DEFAULT};
+                                           base::FEATURE_ENABLED_BY_DEFAULT};
 #endif  // defined(OS_WIN) && !defined(COMPONENT_BUILD)
 
 enum AppLoadedInTabSource {