[Bindings] Create and use V8 context snapshots

gin/v8_initializer.h

Index: gin/v8_initializer.h
diff --git a/gin/v8_initializer.h b/gin/v8_initializer.h
index 7d16c3eb6d940e39d2ba9ad5b1f4ba22eddb753a..8601b15238e12635365e632d538004d9dc3841a7 100644
--- a/gin/v8_initializer.h
+++ b/gin/v8_initializer.h
@@ -76,6 +76,20 @@ class GIN_EXPORT V8Initializer {
 #endif
 
 #endif  // V8_USE_EXTERNAL_STARTUP_DATA
+
+  // Load V8 context snapshot from user provided platform file descriptors.
+  // Other details are same with LoadV8SnapshotFromFD.
+  static void LoadV8ContextSnapshotFromFD(base::PlatformFile snapshot_fd,
+                                          int64_t snapshot_offset,
+                                          int64_t snapshot_size);
+
+  // Load V8 context snapshot from default resources, if they are available.
+  static void LoadV8ContextSnapshot();
+
+  // Get address and size information for currently loaded V8 context snapshot.
+  // If no snapshot is loaded, the return values are nullptr and 0.
+  static void GetV8ContextSnapshotData(const char** snapshot_data_out,
+                                       int* snapshot_size_out);
 };
 
 }  // namespace gin