Revert of Set scaling limit at 320 * 180 for all implementations. (pa…

…tchset #2 id:20001 of https://codereview.webrtc.org/2709153002/ )

Reason for revert:
Looks like webrtc_perf_test started failing on linux, mac and windows after this cl landed.

Example failure:

https://build.chromium.org/p/client.webrtc.perf/builders/Linux%20Trusty/builds/1386/steps/webrtc_perf_tests/logs/stdio

[ RUN      ] CallPerfTest.ReceivesCpuOveruseAndUnderuse
../../webrtc/call/call_perf_tests.cc:522: Failure
Value of: Wait()
  Actual: false
Expected: true
Timed out before receiving an overuse callback.
[  FAILED  ] CallPerfTest.ReceivesCpuOveruseAndUnderuse (120056 ms)

Original issue's description:
> Set scaling limit at 320 * 180 for all implementations.
>
> The MediaCodec decoder on android has trouble decoding video at
> so low resolutions. We set the limit a bit higher for all implementations
> pending a robust software fallback implementation for MediaCodec.
>
> BUG=webrtc:7206
>
> Review-Url: https://codereview.webrtc.org/2709153002
> Cr-Commit-Position: refs/heads/master@{#16798}
> Committed: https://chromium.googlesource.com/external/webrtc/+/560ddb7321f2ae42ff1eb4c79d7c65d59f61dfe2

[email protected],[email protected],[email protected]
# Not skipping CQ checks because original CL landed more than 1 days ago.
BUG=webrtc:7206

Review-Url: https://codereview.webrtc.org/2711913007
Cr-Commit-Position: refs/heads/master@{#16839}

webrtc/video/vie_encoder.cc

@@ -35,12 +35,14 @@ using DegradationPreference = VideoSendStream::DegradationPreference;
 
 // Time interval for logging frame counts.
 const int64_t kFrameLogIntervalMs = 60000;
-
 // We will never ask for a resolution lower than this.
+#if defined(WEBRTC_ANDROID)
 // TODO(kthelgason): Lower this limit when better testing
 // on MediaCodec and fallback implementations are in place.
-// See https://bugs.chromium.org/p/webrtc/issues/detail?id=7206
 const int kMinPixelsPerFrame = 320 * 180;
+#else
+const int kMinPixelsPerFrame = 120 * 90;
+#endif
 
 // The maximum number of frames to drop at beginning of stream
 // to try and achieve desired bitrate.