camera3: Update filterDensity, availableFilterDensity tags.

Change-Id: I27cdf25e370f30637a1e027a57145b0276e5fb0f
diff --git a/camera/docs/docs.html b/camera/docs/docs.html
index 7c56850..fd173e7 100644
--- a/camera/docs/docs.html
+++ b/camera/docs/docs.html
@@ -6186,12 +6186,11 @@
             </td> <!-- entry_type -->
 
             <td class="entry_description">
-              <p>State of lens neutral density
-filter(s)</p>
+              <p>State of lens neutral density filter(s).<wbr/></p>
             </td>
 
             <td class="entry_units">
-              number of stops of filtering
+              Steps of Exposure Value (EV).<wbr/>
             </td>
 
             <td class="entry_range">
@@ -6210,8 +6209,17 @@
           </tr>
           <tr class="entry_cont">
             <td class="entry_details" colspan="5">
-              <p>Will not be supported on most devices.<wbr/> Can only
-pick from supported list</p>
+              <p>This will not be supported on most camera devices.<wbr/> On devices
+where this is supported,<wbr/> this may only be set to one of the
+values included in <a href="#static_android.lens.info.availableFilterDensities">android.<wbr/>lens.<wbr/>info.<wbr/>available<wbr/>Filter<wbr/>Densities</a>.<wbr/></p>
+<p>Lens filters are typically used to lower the amount of light the
+sensor is exposed to (measured in steps of EV).<wbr/> As used here,<wbr/> an EV
+step is the standard logarithmic representation,<wbr/> which are
+non-negative,<wbr/> and inversely proportional to the amount of light
+hitting the sensor.<wbr/>  For example,<wbr/> setting this to 0 would result
+in no reduction of the incoming light,<wbr/> and setting this to 2 would
+mean that the filter is set to reduce incoming light by two stops
+(allowing 1/<wbr/>4 of the prior amount of light to the sensor).<wbr/></p>
             </td>
           </tr>
 
@@ -6465,15 +6473,15 @@
             </td> <!-- entry_type -->
 
             <td class="entry_description">
-              <p>List of supported ND filter
-values</p>
+              <p>List of supported neutral density filter values for
+<a href="#controls_android.lens.filterDensity">android.<wbr/>lens.<wbr/>filter<wbr/>Density</a>.<wbr/></p>
             </td>
 
             <td class="entry_units">
             </td>
 
             <td class="entry_range">
-              <p>one entry required,<wbr/> &gt;= 0</p>
+              <p>At least one value is required.<wbr/> Values must be &gt;= 0.<wbr/></p>
             </td>
 
             <td class="entry_tags">
@@ -6488,10 +6496,10 @@
           </tr>
           <tr class="entry_cont">
             <td class="entry_details" colspan="5">
-              <p>If not available,<wbr/> only setting is 0.<wbr/> Otherwise,<wbr/>
-lists the available exposure index values for dimming
-(2 would mean the filter is set to reduce incoming
-light by two stops)</p>
+              <p>If changing <a href="#controls_android.lens.filterDensity">android.<wbr/>lens.<wbr/>filter<wbr/>Density</a> is not supported,<wbr/>
+availableFilterDensities must contain only 0.<wbr/> Otherwise,<wbr/> this
+list contains only the exact filter density values available on
+this camera device.<wbr/></p>
             </td>
           </tr>
 
@@ -7077,12 +7085,11 @@
             </td> <!-- entry_type -->
 
             <td class="entry_description">
-              <p>State of lens neutral density
-filter(s)</p>
+              <p>State of lens neutral density filter(s).<wbr/></p>
             </td>
 
             <td class="entry_units">
-              number of stops of filtering
+              Steps of Exposure Value (EV).<wbr/>
             </td>
 
             <td class="entry_range">
@@ -7101,8 +7108,17 @@
           </tr>
           <tr class="entry_cont">
             <td class="entry_details" colspan="5">
-              <p>Will not be supported on most devices.<wbr/> Can only
-pick from supported list</p>
+              <p>This will not be supported on most camera devices.<wbr/> On devices
+where this is supported,<wbr/> this may only be set to one of the
+values included in <a href="#static_android.lens.info.availableFilterDensities">android.<wbr/>lens.<wbr/>info.<wbr/>available<wbr/>Filter<wbr/>Densities</a>.<wbr/></p>
+<p>Lens filters are typically used to lower the amount of light the
+sensor is exposed to (measured in steps of EV).<wbr/> As used here,<wbr/> an EV
+step is the standard logarithmic representation,<wbr/> which are
+non-negative,<wbr/> and inversely proportional to the amount of light
+hitting the sensor.<wbr/>  For example,<wbr/> setting this to 0 would result
+in no reduction of the incoming light,<wbr/> and setting this to 2 would
+mean that the filter is set to reduce incoming light by two stops
+(allowing 1/<wbr/>4 of the prior amount of light to the sensor).<wbr/></p>
             </td>
           </tr>