[AW] DevUI: always show crashes for default channel

Crash keys can be absent (null) in some cases like if it's a crash from
an old version. Switch statements in java assume non-null values which
causes NPE when checking for channel info on old crashes. To avoid this
, we will use getCrashKeyOrDefault method.

In addition, always show crashes if they are from UNKOWN/DEFAULT
channel to avoid hiding crashes from older versions.

Fixed: 1093898
Test: Build default channel, trigger a crash.
Test: Manually remove channel info from log file and open the crash UI
Change-Id: I1a445d59a267cb7f41b400b36caa7bf7a31296e8
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2243291
Commit-Queue: Hazem Ashmawy <hazems@chromium.org>
Reviewed-by: Nate Fischer <ntfschr@chromium.org>
Cr-Commit-Position: refs/heads/master@{#777970}

android_webview/nonembedded/java/src/org/chromium/android_webview/devui/CrashesListFragment.java

@@ -330,8 +330,13 @@ public class CrashesListFragment extends DevUiBaseFragment {
                     WebViewCrashInfoCollector crashCollector = new WebViewCrashInfoCollector();
                     // Only show crashes from the same WebView channel, which usually means the
                     // same package.
-                    List<CrashInfo> crashes = crashCollector.loadCrashesInfo(crashInfo
-                            -> getCrashInfoChannel(crashInfo) == VersionConstants.CHANNEL);
+                    List<CrashInfo> crashes = crashCollector.loadCrashesInfo(crashInfo -> {
+                        @Channel
+                        int channel = getCrashInfoChannel(crashInfo);
+                        // Always show the crash if the channel is unknown (to handle missing
+                        // channel info for example for crashes from older versions).
+                        return channel == Channel.DEFAULT || channel == VersionConstants.CHANNEL;
+                    });
                     if (crashes.size() > MAX_CRASHES_NUMBER) {
                         return crashes.subList(0, MAX_CRASHES_NUMBER);
                     }
@@ -362,8 +367,8 @@ public class CrashesListFragment extends DevUiBaseFragment {
     }
 
     @Channel
-    private static int getCrashInfoChannel(CrashInfo c) {
-        switch (c.getCrashKey(CrashInfo.WEBVIEW_CHANNEL_KEY)) {
+    private static int getCrashInfoChannel(@NonNull CrashInfo c) {
+        switch (c.getCrashKeyOrDefault(CrashInfo.WEBVIEW_CHANNEL_KEY, "default")) {
             case "canary":
                 return Channel.CANARY;
             case "dev":