Disable MainThreadFreezeDetection on tests

The main thread test interfers with the EarlGrey synchromization.
If a tests enables metrics, any subsequent sync will wait forever.
Disable MainThreadFreezeDetection on tests.

Bug: 1070286
Change-Id: I96381b423f9915f22015bfe1af264e3ce51697ed
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2151517Reviewed-by: Mark Cogan <marq@chromium.org>
Commit-Queue: Olivier Robin <olivierrobin@chromium.org>
Cr-Commit-Position: refs/heads/master@{#759715}

ios/chrome/app/tests_fake_hook.mm

@@ -28,6 +28,9 @@ bool DisableSigninRecallPromo() {
 bool DisableUpdateService() {
   return false;
 }
+bool DisableMainThreadFreezeDetection() {
+  return false;
+}
 policy::ConfigurationPolicyProvider* GetOverriddenPlatformPolicyProvider() {
   return nullptr;
 }

ios/chrome/app/tests_hook.h

@@ -36,6 +36,11 @@ bool DisableSigninRecallPromo();
 // infobar won't be shown during testing.
 bool DisableUpdateService();
 
+// The main thread freeze detection is interfering with the EarlGrey
+// synchronization.
+// Return true if it should be disabled.
+bool DisableMainThreadFreezeDetection();
+
 // Returns a policy provider that should be installed as the platform policy
 // provider when testing. May return nullptr.
 policy::ConfigurationPolicyProvider* GetOverriddenPlatformPolicyProvider();

ios/chrome/browser/crash_report/BUILD.gn

@@ -26,6 +26,7 @@ source_set("crash_report") {
     "//base",
     "//components/crash/core/common",
     "//components/upload_list",
+    "//ios/chrome/app:tests_hook",
     "//ios/chrome/browser",
     "//ios/chrome/browser/browser_state",
     "//ios/chrome/browser/crash_report/breadcrumbs",

ios/chrome/browser/crash_report/main_thread_freeze_detector.mm

@@ -6,6 +6,7 @@
 
 #include "base/metrics/histogram_macros.h"
 #include "base/time/time.h"
+#include "ios/chrome/app/tests_hook.h"
 #include "ios/chrome/browser/crash_report/breakpad_helper.h"
 #import "third_party/breakpad/breakpad/src/client/ios/Breakpad.h"
 #import "third_party/breakpad/breakpad/src/client/ios/BreakpadController.h"
@@ -110,7 +111,8 @@ void LogRecoveryTime(base::TimeDelta time) {
 }
 
 - (void)start {
-  if (self.delay == 0 || self.running || !_enabled) {
+  if (self.delay == 0 || self.running || !_enabled ||
+      tests_hook::DisableMainThreadFreezeDetection()) {
     return;
   }
   self.running = YES;

ios/chrome/test/earl_grey/eg_tests_hook.mm

@@ -37,6 +37,10 @@ bool DisableUpdateService() {
   return true;
 }
 
+bool DisableMainThreadFreezeDetection() {
+  return true;
+}
+
 policy::ConfigurationPolicyProvider* GetOverriddenPlatformPolicyProvider() {
   if (base::CommandLine::ForCurrentProcess()->HasSwitch(
           "com.apple.configuration.managed")) {