[core] Prepare style observer interfaces for source reloading

* Renamed {Source,Tile}Observer::onNeedsRepaint to onTileUpdated. Messages should be in terms of what happened to the observed object, not in terms of what the observer needs to do. This also removes a confusing overlap of virtual methods on StyleObserver.
* Added style::Observer::onUpdate(Update). This is also a violation of the above rule, but I'm hopeful that it will disappear when update batching is implemented.

1 files changed, 2 insertions, 7 deletions

diff --git a/src/mbgl/style/observer.hpp b/src/mbgl/style/observer.hpp
index c4d31ae249..41b1b46da7 100644
--- a/src/mbgl/style/observer.hpp
+++ b/src/mbgl/style/observer.hpp
@@ -3,6 +3,7 @@
 #include <mbgl/text/glyph_store_observer.hpp>
 #include <mbgl/sprite/sprite_store_observer.hpp>
 #include <mbgl/style/source_observer.hpp>
+#include <mbgl/map/update.hpp>
 
 namespace mbgl {
 namespace style {
@@ -11,13 +12,7 @@ class Observer : public GlyphStoreObserver,
                  public SpriteStoreObserver,
                  public SourceObserver {
 public:
-    /**
-     * In addition to the individual glyph, sprite, and source events, the
-     * following "rollup" events are provided for convenience. They are
-     * strictly additive; e.g. when a source is loaded, both `onSourceLoaded`
-     * and `onNeedsRepaint` will be called.
-     */
-    void onNeedsRepaint() override {}
+    virtual void onUpdate(Update) {}
     virtual void onStyleError() {}
     virtual void onResourceError(std::exception_ptr) {}
 };