Rename SyncService state getters to refer to Sync-the-feature

This renames IsSyncActive to IsSyncFeatureActive and CanSyncStart to
CanSyncFeatureStart, to make clear that these refer to Sync-the-feature,
not Sync-the-transport.
No functional changes.

TBRing lots of call site updates
TBR=jochen

Bug: 856179
Cq-Include-Trybots: luci.chromium.try:ios-simulator-cronet;luci.chromium.try:ios-simulator-full-configs
Change-Id: I091d60173c5b843cfd03e9b8095b8b83f2363753
Reviewed-on: https://chromium-review.googlesource.com/1224381
Commit-Queue: Marc Treib <[email protected]>
Reviewed-by: Mikel Astiz <[email protected]>
Cr-Commit-Position: refs/heads/master@{#591714}
diff --git a/components/sync/driver/sync_service.cc b/components/sync/driver/sync_service.cc
index 867251da..35f80f5 100644
--- a/components/sync/driver/sync_service.cc
+++ b/components/sync/driver/sync_service.cc
@@ -21,7 +21,7 @@
          IsAuthenticatedAccountPrimary();
 }
 
-bool SyncService::CanSyncStart() const {
+bool SyncService::CanSyncFeatureStart() const {
   return GetDisableReasons() == DISABLE_REASON_NONE;
 }
 
@@ -41,7 +41,7 @@
   return false;
 }
 
-bool SyncService::IsSyncActive() const {
+bool SyncService::IsSyncFeatureActive() const {
   if (!IsSyncFeatureEnabled()) {
     return false;
   }