Split some download CHECK message into a LOG message

CHECK messages are discarded for release build.
Using a separate LOG message should give us the error message
in logcat

BUG=1029746

Change-Id: Ia333ee1261ca33c0d9538a5f132af92ae394e347
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1972233Reviewed-by: Xing Liu <xingliu@chromium.org>
Commit-Queue: Min Qin <qinmin@chromium.org>
Cr-Commit-Position: refs/heads/master@{#725688}

components/download/internal/common/download_item_impl.cc

@@ -1468,9 +1468,14 @@ void DownloadItemImpl::Start(
     URLLoaderFactoryProvider::URLLoaderFactoryProviderPtr
         url_loader_factory_provider) {
   DCHECK_CALLED_ON_VALID_THREAD(thread_checker_);
-  CHECK(!download_file_) << "last interrupt reason: "
-                         << DownloadInterruptReasonToString(last_reason_)
-                         << ", state: " << DebugDownloadStateString(state_);
+  if (download_file_) {
+    LOG(ERROR) << "last interrupt reason: "
+               << DownloadInterruptReasonToString(last_reason_)
+               << ", state: " << DebugDownloadStateString(state_)
+               << ", state before last interruption: "
+               << DebugDownloadStateString(state_before_interruption_);
+  }
+  CHECK(!download_file_);
   DVLOG(20) << __func__ << "() this=" << DebugString(true);
   RecordDownloadCountWithSource(START_COUNT, download_source_);
 
@@ -2116,6 +2121,7 @@ void DownloadItemImpl::InterruptWithPartialState(
   // target-pending, which is something we don't want to do. Perhaps we should
   // explicitly transition to target-resolved prior to switching to interrupted.
   DCHECK_EQ(last_reason_, reason);
+  state_before_interruption_ = state_;
   TransitionTo(INTERRUPTED_INTERNAL);
   delegate_->DownloadInterrupted(this);
   AutoResumeIfValid();

components/download/public/common/download_item_impl.h

@@ -730,6 +730,10 @@ class COMPONENTS_DOWNLOAD_EXPORT DownloadItemImpl
   // The current state of this download.
   DownloadInternalState state_ = INITIAL_INTERNAL;
 
+  // The state before download was interrupted.
+  // Remove this once http://crbug.com/1029746 is fixed.
+  DownloadInternalState state_before_interruption_ = INITIAL_INTERNAL;
+
   // Current danger type for the download.
   DownloadDangerType danger_type_ = DOWNLOAD_DANGER_TYPE_NOT_DANGEROUS;