Fix FrameSizeTestsLarge unit-test on 32-bit arch.

If the img allocation fails the test used to crash before on
32 bit architecture. This patch uses null check on img in
FillFrame. Also, if the first frame initialization has not been
conducted VPX_CODEC_ERROR is expected to return rather than
VPX_CODEC_OK.

Change-Id: I5c4e59c156374009012d280d6ff971a89b43c11f

test/encode_test_driver.cc

@@ -69,7 +69,10 @@ void Encoder::EncodeFrameInternal(const VideoSource &video,
 void Encoder::Flush() {
   const vpx_codec_err_t res = vpx_codec_encode(&encoder_, NULL, 0, 0, 0,
                                                deadline_);
-  ASSERT_EQ(VPX_CODEC_OK, res) << EncoderError();
+  if (!encoder_.priv)
+    ASSERT_EQ(VPX_CODEC_ERROR, res) << EncoderError();
+  else
+    ASSERT_EQ(VPX_CODEC_OK, res) << EncoderError();
 }
 
 void EncoderTest::InitializeConfig() {

test/video_source.h

@@ -142,7 +142,7 @@ class DummyVideoSource : public VideoSource {
   }
 
  protected:
-  virtual void FillFrame() { memset(img_->img_data, 0, raw_sz_); }
+  virtual void FillFrame() { if (img_) memset(img_->img_data, 0, raw_sz_); }
 
   vpx_image_t *img_;
   size_t       raw_sz_;
@@ -170,11 +170,13 @@ class RandomVideoSource : public DummyVideoSource {
   // 15 frames of noise, followed by 15 static frames. Reset to 0 rather
   // than holding previous frames to encourage keyframes to be thrown.
   virtual void FillFrame() {
-    if (frame_ % 30 < 15)
-      for (size_t i = 0; i < raw_sz_; ++i)
-        img_->img_data[i] = rnd_.Rand8();
-    else
-      memset(img_->img_data, 0, raw_sz_);
+    if (img_) {
+      if (frame_ % 30 < 15)
+        for (size_t i = 0; i < raw_sz_; ++i)
+          img_->img_data[i] = rnd_.Rand8();
+      else
+        memset(img_->img_data, 0, raw_sz_);
+    }
   }
 
   ACMRandom rnd_;