[skottie] Add support for multiple range selectors

Text animators can have more than one range selector.

(depends on https://github.com/bodymovin/bodymovin-extension/pull/21)

TBR=
Change-Id: Id7f73386853f0e0f9e3c0f15d5a87ec1653ba873
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/234319
Reviewed-by: Florin Malita <fmalita@chromium.org>
Commit-Queue: Florin Malita <fmalita@chromium.org>

modules/skottie/src/text/RangeSelector.cpp

@@ -182,6 +182,22 @@ sk_sp<RangeSelector> RangeSelector::Make(const skjson::ObjectValue* jrange,
         return nullptr;
     }
 
+    enum : int32_t {
+             kRange_SelectorType = 0,
+        kExpression_SelectorType = 1,
+
+        // kWiggly_SelectorType = ? (not exported)
+    };
+
+    {
+        const auto type = ParseDefault<int>((*jrange)["t"], kRange_SelectorType);
+        if (type != kRange_SelectorType) {
+            abuilder->log(Logger::Level::kWarning, nullptr,
+                          "Ignoring unsupported selector type '%d'", type);
+            return nullptr;
+        }
+    }
+
     static constexpr Units gUnitMap[] = {
         Units::kPercentage,  // 'r': 1
         Units::kIndex,       // 'r': 2

modules/skottie/src/text/TextAnimator.cpp

@@ -40,7 +40,7 @@ namespace internal {
  * "t": {              // text node
  *   "a": [            // animators list
  *     {               // animator node
- *       "s": {...},   // selector node (TODO)
+ *       "s": {...},   // selector node
  *       "a": {        // animator properties node
  *         "a":  {}    // optional anchor point value
  *         "p":  {},   // optional position value
@@ -63,26 +63,39 @@ sk_sp<TextAnimator> TextAnimator::Make(const skjson::ObjectValue* janimator,
         return nullptr;
     }
 
+    const skjson::ObjectValue* jprops = (*janimator)["a"];
+    if (!jprops) {
+        return nullptr;
+    }
+
     std::vector<sk_sp<RangeSelector>> selectors;
-    if (const skjson::ObjectValue* jselector = (*janimator)["s"]) {
-        // Single range selector for now.
-        if (auto sel = RangeSelector::Make(jselector, abuilder)) {
+
+    // Depending on compat mode and whether more than one selector is present,
+    // BM exports either an array or a single object.
+    if (const skjson::ArrayValue* jselectors = (*janimator)["s"]) {
+        selectors.reserve(jselectors->size());
+        for (const skjson::ObjectValue* jselector : *jselectors) {
+            if (auto sel = RangeSelector::Make(*jselector, abuilder)) {
+                selectors.push_back(std::move(sel));
+            }
+        }
+    } else {
+        if (auto sel = RangeSelector::Make((*janimator)["s"], abuilder)) {
             selectors.reserve(1);
             selectors.push_back(std::move(sel));
         }
     }
 
-    const skjson::ObjectValue* jprops = (*janimator)["a"];
-
-    return jprops
-        ? sk_sp<TextAnimator>(new TextAnimator(std::move(selectors), *jprops, abuilder))
-        : nullptr;
+    return sk_sp<TextAnimator>(new TextAnimator(std::move(selectors), *jprops, abuilder));
 }
 
 void TextAnimator::modulateProps(const DomainMaps& maps, ModulatorBuffer& buf) const {
+    // No selectors -> full coverage.
+    const auto initial_coverage = fSelectors.empty() ? 1.f : 0.f;
+
     // Coverage is scoped per animator.
     for (auto& mod : buf) {
-        mod.coverage = 0;
+        mod.coverage = initial_coverage;
     }
 
     // Accumulate selector coverage.