Add the ability to defer the initialization of the SyzyAsan crash reporter.

syzygy/agent/asan/runtime.h

Index: syzygy/agent/asan/runtime.h
diff --git a/syzygy/agent/asan/runtime.h b/syzygy/agent/asan/runtime.h
index 2336e82a3cdc41ac4e93c774328f47e38866c4e0..f9a5d5679f85762f671852ccdcec4e57ffe3f5a0 100644
--- a/syzygy/agent/asan/runtime.h
+++ b/syzygy/agent/asan/runtime.h
@@ -149,6 +149,9 @@ class AsanRuntime {
   // @names Accessors.
   // {
   uint64_t random_key() const { return random_key_; }
+  bool crash_reporter_initialized() const {
+    return crash_reporter_initialized_;
+  }
   // @}
 
   // Observes a given thread ID, adding it to thread ID set.
@@ -194,6 +197,17 @@ class AsanRuntime {
   // @returns the list of enabled features.
   AsanFeatureSet GetEnabledFeatureSet();
 
+  // Initialize the crash reporter used by the runtime.
+  //
+  // This function should only be called once during the runtime's lifetime,
+  // it could either be called at setup time if the deferred initialization
+  // flag hasn't been set on the command line or later by the instrumented
+  // image.
+  //
+  // Calling this when the crash reporter has already been initialized will
+  // terminate the process.
+  void InitializeCrashReporter();
+
  protected:
   // Propagate the values of the flags to the target modules.
   void PropagateParams();
@@ -327,6 +341,9 @@ class AsanRuntime {
   // is available.
   std::unique_ptr<ReporterInterface> crash_reporter_;
 
+  // Indicates if the crash reporter has been initialized.
+  bool crash_reporter_initialized_;
+
   DISALLOW_COPY_AND_ASSIGN(AsanRuntime);
 };