Adding Video Capture Host MojoLPM fuzzer.

Bug: 1113715
Change-Id: Ia927f27bba18eedf56447fa05afd3bddde679331
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2273128
Commit-Queue: Clovis PJ <clovispj@google.com>
Reviewed-by: Guido Urdaneta <guidou@chromium.org>
Reviewed-by: Max Moroz <mmoroz@chromium.org>
Cr-Commit-Position: refs/heads/master@{#806672}

content/test/fuzzer/BUILD.gn

@@ -254,3 +254,30 @@ fuzzer_test("indexed_db_leveldb_coding_decodeidbkeypath_fuzzer") {
   seed_corpus =
       "../../browser/indexed_db/fuzzer_corpus/encoded_indexed_db_key_path"
 }
+
+# Fuzzer only supports linux. As we use a `V4L2CaptureDevice`, which is only
+# usable on linux through `VideoCaptureDeviceFactoryLinux`.
+if (is_linux) {
+  mojolpm_fuzzer_test("video_capture_host_mojolpm_fuzzer") {
+    sources = [ "video_capture_host_mojolpm_fuzzer.cc" ]
+
+    proto_source = "video_capture_host_mojolpm_fuzzer.proto"
+
+    deps = [
+      "//base/test:test_support",
+      "//content/browser:for_content_tests",
+      "//content/public/browser:browser",
+      "//content/test:content_unittests",
+      "//content/test:test_support",
+      "//media:test_support",
+      "//media/capture:capture_lib",
+      "//media/capture:test_support",
+      "//services/network:test_support",
+      "//storage/browser:test_support",
+      "//third_party/blink/public/common:common",
+      "//third_party/icu:icudata",
+    ]
+
+    proto_deps = [ "//media/capture/mojom:video_capture_mojolpm" ]
+  }
+}

content/test/fuzzer/video_capture_host_mojolpm_fuzzer.proto

+syntax = "proto2";
+
+package content.fuzzing.video_capture_host.proto;
+
+import "media/capture/mojom/video_capture.mojom.mojolpm.proto";
+
+// Bind a new VideoCaptureHost remote
+message NewVideoCaptureHostAction {
+  required uint32 id = 1;
+  required uint32 render_process_id = 2;
+}
+
+// A wrapper message for all remote actions. It requires further specifying
+// the `render_process_id` and `device_index` to identify which session id to
+// inject into the call. So the call correctly acts for a specific device.
+message VideoCaptureHostDeviceRemoteAction {
+  required uint32 render_process_id = 1;
+  required uint32 device_index = 2;
+  required mojolpm.media.mojom.VideoCaptureHost.RemoteAction remote_action = 3;
+}
+
+// Run the specific sequence for (an indeterminate) period. This is not
+// intended to create a specific ordering, but to allow the fuzzer to delay a
+// later task until previous tasks have completed.
+message RunThreadAction {
+  enum ThreadId {
+    IO = 0;
+    UI = 1;
+  }
+
+  required ThreadId id = 1;
+}
+
+// Actions that can be performed by the fuzzer.
+message Action {
+  oneof action {
+    RunThreadAction run_thread = 1;
+
+    NewVideoCaptureHostAction new_video_capture_host = 2;
+    VideoCaptureHostDeviceRemoteAction video_capture_host_device_remote_action =
+        3;
+    mojolpm.media.mojom.VideoCaptureObserver.ReceiverAction
+        video_capture_observer_receiver_action = 4;
+  }
+}
+
+// Sequence provides a level of indirection which allows Testcase to compactly
+// express repeated sequences of actions.
+message Sequence {
+  repeated uint32 action_indexes = 1 [packed = true];
+}
+
+// Testcase is the top-level message type interpreted by the fuzzer.
+message Testcase {
+  repeated Action actions = 1;
+  repeated Sequence sequences = 2;
+  repeated uint32 sequence_indexes = 3 [packed = true];
+}