ambient: Change photo transition interval to 1 min

Bug: b/139953713, b/162782654
Test: manual
Change-Id: I5d3bda0f2eba4cfc3adaa155d079666b3b33c2d5
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2337285Reviewed-by: Xiaohui Chen <xiaohuic@chromium.org>
Commit-Queue: Tao Wu <wutao@chromium.org>
Cr-Commit-Position: refs/heads/master@{#794755}

ash/ambient/ambient_constants.h

@@ -17,7 +17,7 @@ constexpr base::TimeDelta kAnimationDuration =
 // The default interval to refresh photos.
 // TODO(b/139953713): Change to a correct time interval.
 constexpr base::TimeDelta kPhotoRefreshInterval =
-    base::TimeDelta::FromSeconds(5);
+    base::TimeDelta::FromSeconds(60);
 
 // Directory name of ambient mode.
 constexpr char kAmbientModeDirectoryName[] = "ambient-mode";

ash/ambient/ambient_photo_controller.cc

@@ -55,10 +55,8 @@ constexpr int kTopicsBatchSize = 2;
 
 // The upper bound of delay to the fetch topics. An random value will be
 // generated in the range of |kTopicFetchDelayMax|/2 to |kTopicFetchDelayMax|.
-
-// TODO(b/139953713): Change to a correct time interval.
-// E.g. it will be max 36 seconds if we want to fetch 50 batches in 30 mins.
-constexpr base::TimeDelta kTopicFetchDelayMax = base::TimeDelta::FromSeconds(3);
+constexpr base::TimeDelta kTopicFetchDelayMax =
+    base::TimeDelta::FromSeconds(36);
 
 constexpr int kMaxImageSizeInBytes = 5 * 1024 * 1024;