Add IsRenderFrameLive to Android Webview crashkey whitelist.

This is a temporary addition to help track down a bug that only occurs
in webview in the wild.

Bug: 1006814,1056426
Change-Id: If5be906c7faf94ef994389f7b286ef2a70bba5b9
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2087236
Commit-Queue: Fergal Daly <fergal@chromium.org>
Commit-Queue: Robert Sesek <rsesek@chromium.org>
Auto-Submit: Fergal Daly <fergal@chromium.org>
Reviewed-by: Robert Sesek <rsesek@chromium.org>
Cr-Commit-Position: refs/heads/master@{#746828}

android_webview/common/crash_reporter/crash_keys.cc

@@ -51,6 +51,8 @@ const char* const kWebViewCrashKeyWhiteList[] = {
     "mojo-message-error__3",
     "mojo-message-error__4",
     "total-discardable-memory-allocated",
+    // TODO(https://crbug.com/1006814): Remove this.
+    "IsRenderFrameLive",
 
     // GWP-ASan
     gwp_asan::kMallocCrashKey,