[core] Remove unused 'Throttler' class.

Throttler was previously used to control how frequently background placement ran.

cmake/core-files.cmake

@@ -748,8 +748,6 @@ set(MBGL_CORE_FILES
     src/mbgl/util/stopwatch.hpp
     src/mbgl/util/string.cpp
     src/mbgl/util/thread_local.hpp
-    src/mbgl/util/throttler.cpp
-    src/mbgl/util/throttler.hpp
     src/mbgl/util/tile_coordinate.hpp
     src/mbgl/util/tile_cover.cpp
     src/mbgl/util/tile_cover.hpp

src/mbgl/tile/geometry_tile.hpp

@@ -5,7 +5,6 @@
 #include <mbgl/renderer/image_manager.hpp>
 #include <mbgl/text/glyph_manager.hpp>
 #include <mbgl/util/feature.hpp>
-#include <mbgl/util/throttler.hpp>
 #include <mbgl/actor/actor.hpp>
 #include <mbgl/geometry/feature_index.hpp>
 

src/mbgl/util/throttler.cpp

@@ -1,36 +0,0 @@
-#include <mbgl/util/throttler.hpp>
-
-namespace mbgl {
-namespace util {
-
-Throttler::Throttler(Duration frequency_, std::function<void()>&& function_)
-    : frequency(frequency_)
-    , function(std::move(function_))
-    , pendingInvocation(false)
-    , lastInvocation(TimePoint::min())
-{}
-
-void Throttler::invoke() {
-    if (pendingInvocation) {
-        return;
-    }
-    
-    Duration timeToNextInvocation = lastInvocation == TimePoint::min()
-        ? Duration::zero()
-        : (lastInvocation + frequency) - Clock::now();
-    
-    if (timeToNextInvocation <= Duration::zero()) {
-        lastInvocation = Clock::now();
-        function();
-    } else {
-        pendingInvocation = true;
-        timer.start(timeToNextInvocation, Duration::zero(), [this]{
-            pendingInvocation = false;
-            lastInvocation = Clock::now();
-            function();
-        });
-    }
-}
-
-} // namespace util
-} // namespace mbgl

src/mbgl/util/throttler.hpp

@@ -1,22 +0,0 @@
-#include <mbgl/util/chrono.hpp>
-#include <mbgl/util/timer.hpp>
-
-namespace mbgl {
-namespace util {
-
-class Throttler {
-public:
-    Throttler(Duration frequency, std::function<void()>&& function);
-    
-    void invoke();
-private:
-    Duration frequency;
-    std::function<void()> function;
-    
-    Timer timer;
-    bool pendingInvocation;
-    TimePoint lastInvocation;
-};
-
-} // namespace util
-} // namespace mbgl