Add file capturer to AppRTCMobile on simulator.

To achieve this, the CL does the following
- Adds sample mp4 video
- Refactors the existing RTCFileVideoCapturer to achieve continious
capture and adds tests.

Bug: webrtc:8406
Change-Id: Ibc0891176c58ec9053b42e340d2113036e7199ec
Reviewed-on: https://webrtc-review.googlesource.com/12180
Reviewed-by: Anders Carlsson <andersc@webrtc.org>
Reviewed-by: Magnus Jedvert <magjed@webrtc.org>
Commit-Queue: Daniela Jovanoska Petrenko <denicija@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#20598}

sdk/objc/Framework/UnitTests/RTCFileVideoCapturer_xctest.mm

@@ -0,0 +1,111 @@
+/*
+ *  Copyright 2017 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#import "WebRTC/RTCFileVideoCapturer.h"
+
+#import <XCTest/XCTest.h>
+
+#include "rtc_base/gunit.h"
+
+NSString *const kTestFileName = @"foreman.mp4";
+static const int kTestTimeoutMs = 5 * 1000;  // 5secs.
+
+@interface MockCapturerDelegate : NSObject <RTCVideoCapturerDelegate>
+
+@property(nonatomic, assign) NSInteger capturedFramesCount;
+
+@end
+
+@implementation MockCapturerDelegate
+@synthesize capturedFramesCount = _capturedFramesCount;
+
+- (void)capturer:(RTCVideoCapturer *)capturer didCaptureVideoFrame:(RTCVideoFrame *)frame {
+  self.capturedFramesCount++;
+}
+
+@end
+
+NS_CLASS_AVAILABLE_IOS(10)
+@interface RTCFileVideoCapturerTests : XCTestCase
+
+@property(nonatomic, strong) RTCFileVideoCapturer *capturer;
+@property(nonatomic, strong) MockCapturerDelegate *mockDelegate;
+
+@end
+
+@implementation RTCFileVideoCapturerTests
+@synthesize capturer = _capturer;
+@synthesize mockDelegate = _mockDelegate;
+
+- (void)setUp {
+  self.mockDelegate = [[MockCapturerDelegate alloc] init];
+  self.capturer = [[RTCFileVideoCapturer alloc] initWithDelegate:self.mockDelegate];
+}
+
+- (void)tearDown {
+  self.capturer = nil;
+  self.mockDelegate = nil;
+}
+
+- (void)testCaptureWhenFileNotInBundle {
+  __block BOOL errorOccured = NO;
+
+  RTCFileVideoCapturerErrorBlock errorBlock = ^void(NSError *error) {
+    errorOccured = YES;
+  };
+
+  [self.capturer startCapturingFromFileNamed:@"not_in_bundle.mov" onError:errorBlock];
+  ASSERT_TRUE_WAIT(errorOccured, kTestTimeoutMs);
+}
+
+- (void)testSecondStartCaptureCallFails {
+  __block BOOL secondError = NO;
+
+  RTCFileVideoCapturerErrorBlock firstErrorBlock = ^void(NSError *error) {
+    // This block should never be called.
+    NSLog(@"Error: %@", [error userInfo]);
+    ASSERT_TRUE(false);
+  };
+
+  RTCFileVideoCapturerErrorBlock secondErrorBlock = ^void(NSError *error) {
+    secondError = YES;
+  };
+
+  [self.capturer startCapturingFromFileNamed:kTestFileName onError:firstErrorBlock];
+  [self.capturer startCapturingFromFileNamed:kTestFileName onError:secondErrorBlock];
+
+  ASSERT_TRUE_WAIT(secondError, kTestTimeoutMs);
+}
+
+- (void)testStartStopCapturer {
+  if (@available(iOS 10, *)) {
+    [self.capturer startCapturingFromFileNamed:kTestFileName onError:nil];
+
+    __block BOOL done = NO;
+    __block NSInteger capturedFrames = -1;
+    NSInteger capturedFramesAfterStop = -1;
+
+    // We're dispatching the `stopCapture` with delay to ensure the capturer has
+    // had the chance to capture several frames.
+    dispatch_time_t captureDelay = dispatch_time(DISPATCH_TIME_NOW, 2 * NSEC_PER_SEC);  // 2secs.
+    dispatch_after(captureDelay, dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{
+      capturedFrames = self.mockDelegate.capturedFramesCount;
+      [self.capturer stopCapture];
+      done = YES;
+    });
+    WAIT(done, kTestTimeoutMs);
+
+    capturedFramesAfterStop = self.mockDelegate.capturedFramesCount;
+    ASSERT_TRUE(capturedFrames != -1);
+    ASSERT_EQ(capturedFrames, capturedFramesAfterStop);
+  }
+}
+
+@end